April 27, 2007


VIA EDGAR
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Mr. Sonny Oh
U.S. Securities and Exchange Commission
100 F Street, NE
Washington, DC 20549


Re:  Comments on Post-Effective  Amendment No. 29 to the Registration  Statement
     on Form  N-1A of  Mutual  of  America  Investment  Corporation  (File  Nos.
     33-6486; 811-5084)


Dear Mr. Oh:

     On  behalf of the  above-referenced  registrant,  set  forth  below are the
comments  that you provided by telephone to me and  Elizabeth  Edson on April 6,
2007, concerning  Post-Effective  Amendment No. 29 to the Registration Statement
on Form  N-1A of Mutual  of  America  Investment  Corporation  (the  "Investment
Company"), which was filed with the SEC on February 12, 2007, and the Investment
Company's  responses  thereto.  The responses  are  reflected in  Post-Effective
Amendment No. 30 to the Investment Company's  Registration  Statement filed with
the SEC today.  Unless otherwise noted,  defined terms have the same meanings as
in the Registration Statement.

     In addition, as Ndenisarya Meekins discussed with you by telephone on April
13, 2006, the Investment Company has made additional revisions to streamline and
clarify the prospectus  disclosure as well as eliminate  unnecessary  repetitive
disclosure. In this process, the prospectus has been reorganized as described in
response to your comments below.

PROSPECTUS


GENERAL
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1.   COMMENT:  On the  front  cover  page,  delete  references  to  unaffiliated
     entities.

     RESPONSE: The Investment Company has made the requested change.

2.   COMMENT:  On the back cover page,  update the telephone  number for the SEC
     Public Reference Room to reflect 1-202-942-8090.



Mr. Sonny Oh
April 27, 2007
Page 2 of 11


     RESPONSE: The Investment Company has made the requested change.

3.   COMMENT: Confirm reference page numbers throughout the prospectus.

     RESPONSE:  The Investment  Company has reviewed the page number  references
     throughout the prospectus and has made appropriate revisions.


SUMMARY OF HOW OUR FUNDS INVEST
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4.   COMMENT:  In  accordance  with Item 4(a) of Form N-1A,  for each  fund,  as
     appropriate,  disclose  whether its investment  objective is fundamental or
     non-fundamental and can be changed without shareholder approval.

     RESPONSE: The Investment Company has made the requested change. Each fund's
     investment   objective  is  non-fundamental  and  may  be  changed  without
     shareholder  approval.  A  general  statement  pertaining  to  each  fund's
     investment objective has been added to page 1 of the revised prospectus.

5.   COMMENT:  In accordance  with Rule 35d-1 of the 1940 Act, for each fund, as
     appropriate,  include  disclosure  regarding the fund's policy to invest at
     least 80% of its assets in securities implicated by its name. Also, include
     the  corresponding  disclosure  that the fund may not change its 80% policy
     without providing shareholders at least 60 days prior written notice.

     RESPONSE:  The Investment Company notes that a general statement pertaining
     to each  applicable  Fund's 80% policy  appeared  in the  section  entitled
     DETAILS ABOUT HOW OUR FUNDS INVEST.  The  Investment  Company has clarified
     this  disclosure  and moved it to page 1 of the revised  prospectus  in the
     section entitled SUMMARY OF HOW OUR FUNDS INVEST.

6.   COMMENT:  In  accordance  with Item 4(b)(1) and (c) of Form N-1A,  for each
     fund,  confirm the  principal  investment  strategies  and confirm that the
     corresponding  principal risks are disclosed in the fund summary.  For each
     fund, when principal investment strategies are added to the summary, please
     add disclosure  reflecting the corresponding  principal risk resulting from
     that added strategy.

     RESPONSE: The Investment Company has reviewed the investment strategies and
     confirmed  that the risks for each principal  investment  strategy has been


Mr. Sonny Oh
April 27, 2007
Page 3 of 11

     included.   In  addition,  as  noted  above,  the  Investment  Company  has
     reorganized the prospectus disclosure and has moved the risk disclosure for
     all of the funds into a new section entitled PRINCIPAL RISKS.

7.   COMMENT: In accordance with Instruction 6 to Item 4(b)(1) of Form N-1A, for
     each fund, as  appropriate,  disclose any temporary  defensive  policy,  if
     applicable.

     RESPONSE:  No change was made in response to this Comment 7. The Investment
     Company has confirmed  that no Fund,  other than the Composite  Fund, has a
     temporary  defensive  policy.  In addition,  no change has been made to the
     existing disclosure regarding the Composite Fund's policy.

8.   COMMENT: Review and confirm the placement of the section entitled VALUE AND
     GROWTH STOCKS.  It is not clear why this disclosure  appears as part of the
     disclosure  relating to the All  America  Fund.  Additionally,  revise this
     section to include disclosure that the adviser's measure of intrinsic value
     may not be accurate and stocks chosen by the adviser may perform poorly.

     RESPONSE:  The  section  entitled  VALUE AND GROWTH  STOCKS was  originally
     intended  as a  footnote  and  appeared  as it did in the  text  of the All
     America Fund  description as a function of the EDGAR  conversion.  As noted
     above,  the  Investment  Company  has  reorganized  the  disclosure  in the
     prospectus  and  determined  that a clearer way to present the  information
     regarding  value  stocks  and  growth  stocks is in the  section  regarding
     PRINCIPAL RISKS. Each Fund that invests in value or growth stocks now cross
     references an appropriate risk. In addition, the Investment Company revised
     the description of the new value stock risk to include disclosure regarding
     the  adviser's   measure  of  intrinsic   value  and  its  effect  on  fund
     performance.

9.   COMMENT:  In the  section  relating  to the MID CAP  VALUE  FUND,  move the
     following  disclosure into the sub-section  entitled "Risks" for this Fund:
     "Securities  issued by  companies  with  mid-sized  market  capitalizations
     generally  trade  in  lower  volumes  and  are  subject  to  greater,  less
     predictable  price  changes than the  securities  of companies  with larger
     market capitalizations."

     RESPONSE:  As noted  above,  the  Investment  Company has  reorganized  the
     disclosure in the prospectus  and determined  that a clearer way to present
     the information  regarding risks relating to the market  capitalization  of
     companies is to  incorporate  this  disclosure in the new section  entitled
     PRINCIPAL RISKS as "Small cap and mid cap risk" and "Large cap risk."



Mr. Sonny Oh
April 27, 2007
Page 4 of 11

10.  COMMENT:  In the section entitled MARKET  CAPITALIZATIONS OF EQUITY ISSUERS
     confirm  the  defined  range of market  capitalization  for the  Investment
     Company's funds and delete the term "generally."

     RESPONSE:  The  Investment  Company has  confirmed  that each Fund uses the
     market  capitalizations  established  by its benchmark  index to define the
     universe of companies in which it may invest.  The  Investment  Company has
     clarified   the   disclosure   in   the   section   now   entitled   MARKET
     CAPITALIZATIONS.

11.  COMMENT:  In the section  entitled  RISKS OF  INVESTING  IN ANY OF THE BOND
     FUNDS,  add disclosure  that "below  investment-grade  securities are often
     referred to as junk bonds."

     RESPONSE:  As noted  above,  the  Investment  Company has  reorganized  the
     disclosure in the prospectus  and determined  that a clearer way to present
     the  information  previously  included  in the  section  entitled  RISKS OF
     INVESTING  IN ANY OF THE BOND FUNDS is to add a separate  section  entitled
     PRINCIPAL  RISKS that  describes  specific  risks of  investing  in various
     investments.  This new risk section includes  disclosure covering the risks
     of investing in below investment  grade  securities.  Additionally,  in the
     disclosure  for  each  Fund  that  invests  in  "below   investment   grade
     securities,"  the  Investment  Company has confirmed that  disclosure  also
     appears that states  these  securities  are  commonly  referred to as "junk
     bonds."

12.  COMMENT: In the section relating to the INTERNATIONAL FUND, supplementally,
     explain  to the staff the legal  basis for the Fund being  structured  as a
     fund-of-funds and the Fund's ability to invest in ETFs.

     RESPONSE: The Fund is structured as a "fund-of-funds" which is permitted to
     invest in ETFs in  reliance on an  exemptive  order  obtained by  Barclays,
     which permits investment companies (such as the Fund) to invest in its ETFs
     beyond the limits of Section 12(d)(1)(A).

13.  COMMENT:  In the section relating to the  INTERNATIONAL  FUND,  confirm the
     disclosure  regarding  what other  securities  this fund invests in and the
     corresponding  risks  of such  investments.  In  addition,  the  disclosure
     regarding  investing in ETF's should be moved into the summary along with a
     brief description of the risks of investing in ETFs.

     RESPONSE:  The Investment  Company has confirmed the  disclosure  regarding
     what  securities  the Fund will invest in. As noted above,  the  Investment
     Company has  reorganized  the  disclosure in the  prospectus and determined


Mr. Sonny Oh
April 27, 2007
Page 5 of 11

     that a clearer  way to present  the  principal  risks of each  Fund,  is to
     include a separate section of the prospectus  entitled PRINCIPAL RISKS. The
     disclosure  regarding risks of investing in ETFs has been incorporated into
     this new section and a cross reference to the risk has been included in the
     summary for the International Fund.

14.  COMMENT:  In the sections  relating to the BOND FUND and the MID-TERM  BOND
     FUND,  please confirm  whether the funds invest in foreign debt  securities
     and add  appropriate  disclosure  regarding  the  investment  strategy  and
     attendant risks.

     RESPONSE:  The  Investment  Company has confirmed that each fund invests in
     foreign debt securities. Appropriate revisions to the prospectus disclosure
     have been incorporated.

15.  COMMENT:   In  the  section  relating  to  the  TARGET   RETIREMENT  FUNDS,
     supplementally,  explain  to the  staff the  legal  basis  for the  Board's
     ability to transfer assets of a Maturing  Retirement Fund to the Retirement
     Income Fund without shareholder approval

     RESPONSE:  The Board of a Maturing Retirement Fund is permitted to transfer
     the assets of such Fund to the  Retirement  Income Fund in reliance on Rule
     17a-8 of the 1940 Act which permits mergers of affiliated  companies and of
     portfolios within the same investment company without shareholder  approval
     if certain requirements are met. The Board of each such Maturing Retirement
     Fund will  ensure that it has met the  requirements  of Rule 17a-8 prior to
     any such merger.

16.  COMMENT:  In the section relating to the TARGET RETIREMENT  FUNDS,  clarify
     the disclosure  regarding what each fund may invest in. Consider moving the
     Appendix  that shows the  allocation  forward,  or cross  reference  to the
     Appendix.

     RESPONSE:  The  Investment  Company  has made  the  requested  change.  The
     information  previously  reported in Appendix A has been  incorporated into
     the section of the  Prospectus  titled SUMMARY OF HOW OUR FUNDS INVEST as a
     table entitled TARGET ALLOCATION OF THE RETIREMENT  FUNDS.  Because of this
     change,  the Investment  Company has revised the disclosure  regarding each
     Retirement Fund to delete the previous disclosure  regarding how the fund's
     assets are currently allocated.

17.  COMMENT:  In the section relating to the TARGET RETIREMENT FUNDS,  identify
     the Investment Company's Funds in which each Retirement Fund is invested.



Mr. Sonny Oh
April 27, 2007
Page 6 of 11

     RESPONSE:  The change made by the Investment Company in response to Comment
     16  eliminates  the need to make any  further  change in  response  to this
     Comment 17. The new table  entitled  TARGET  ALLOCATION  OF THE  RETIREMENT
     FUNDS  discloses  the  specific  Investment  Company  Funds in  which  each
     Retirement Fund is to be invested when it commences  operations on or after
     July 1, 2007.  However,  all  Investment  Company  Funds are  available for
     investment by the  Retirement  Funds as determined by the Adviser from time
     to time in conformity with each Retirement Fund's allocation model.

18.  COMMENT:  In the  section  relating  to the TARGET  RETIREMENT  FUNDS,  the
     prospectus   discloses  that  the   Retirement   Fund  can  invest  in  the
     International  Fund.  Include  disclosure  of the  risks  of  investing  in
     underlying  funds.  Additionally,  add  risks of  investing  in the  Target
     Retirement  Funds  and  clarify  the  existing  risk  disclosure  regarding
     investing in bond funds and equity mutual funds

     RESPONSE: The Investment Company has made the requested change.

19.  COMMENT: In accordance with Instruction 7 to Item 4(a)(1) of Form N-1A, for
     each fund, as appropriate,  include  disclosure  regarding whether any Fund
     engages in active trading of portfolio  securities to achieve its principal
     investment strategies.

     RESPONSE:  No change  has been made in  response  to this  Comment  19. The
     Investment  Company has confirmed that no Fund engages in active trading of
     portfolio  securities.  In addition,  the Investment  Company has confirmed
     that  current  portfolio  turnover  rates  for the  Funds  are not  high in
     relation  to similar  funds in the  market  place.  Appropriate  disclosure
     regarding portfolio turnover for each Fund is included in the SAI.

20.  COMMENT: For each fund, in accordance with Instruction 4 to Item 4(a)(1) of
     Form N-1A, disclose any policy to concentrate in securities of issuers in a
     particular industry or group of industries, if applicable.

     RESPONSE:  No change  has been made in  response  to this  Comment  20. The
     Investment  Company has confirmed  that no Fund has a policy to concentrate
     its assets in a particular industry or group of industries.


ANNUAL FEES AND EXPENSES TABLE
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21.  COMMENT:  In the line item  regarding  Shareholder  Fees,  replace the term
     "none" with "n/a".


Mr. Sonny Oh
April 27, 2007
Page 7 of 11

     RESPONSE: The Investment Company has made the requested change.

22.  COMMENT:  In the line  item  regarding  Acquired  Fund  Fees and  Expenses,
     confirm the footnote *** disclosure.

     RESPONSE:  The Investment Company has reviewed the footnote  disclosure and
     has made the appropriate revisions.

23.  COMMENT:  In the line  item  regarding  Acquired  Fund  fees and  Expenses,
     confirm that the  calculations  were done in accordance  with  instructions
     3(f)  of  Form  N-1A  Item 3 and  format  the  fee  table  to  reflect  the
     requirements for a fund-of-funds.

     RESPONSE:  The Investment  Company has confirmed that the calculations were
     done in accordance with Form N-1A and has made the appropriate revisions.


EXPENSE EXAMPLE
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24.  COMMENT: In accordance with Instruction 5(b) of Item 3 regarding New Funds,
     confirm that the expense example,  with respect to the  International  Fund
     and each Retirement  Fund,  will provide  disclosure for only one and three
     years.

     RESPONSE: The Investment Company has made the requested change.


MANAGEMENT OF THE FUNDS
- -----------------------

25.  COMMENT: Confirm the management fees disclosed for Equity Index and Mid-Cap
     Index Funds and for International Fund.

     RESPONSE: The Investment Company has confirmed that the management fees are
     correct.


DETAILS ABOUT HOW OUR FUNDS INVEST
- ----------------------------------

26.  COMMENT: In this section discussing EXCHANGE TRADED FUNDS,  consider moving
     the disclosure regarding 1940 Act limits for investments of underlying ETFs
     and related exemptive orders forward in the prospectus.

     RESPONSE:  The  Investment  Company  has made  the  requested  change.  The
     relevant  disclosure  has been  moved into this  section of the  prospectus
     relating specifically to the International Fund.



Mr. Sonny Oh
April 27, 2007
Page 8 of 11


INFORMATION ABOUT FUND SHARES
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27.  COMMENT:  In  accordance  with Item  6(a) of Form  N-1A,  confirm  that the
     section  entitled  PRICING OF FUND  SHARES,  regarding  the  pricing of the
     Allocation  Funds,   Retirement  Funds  and  International  Fund,  includes
     disclosure  that  explains  that the fund's net asset  value is  calculated
     based  upon the net asset  values  of the  registered  open-end  management
     investment companies in which the funds invest.

     Response: The Investment Company has made the requested change.

28.  COMMENT:  In accordance with Item 6(e) of Form N-1A,  revise the disclosure
     in the section entitled  Frequent  PURCHASES AND REDEMPTIONS OF FUND SHARES
     to identify funds that might be more  susceptible to arbitrage and frequent
     trading (i.e. Small Cap Fund and International Fund).

     RESPONSE: The Investment Company has made the requested change.


FINANCIAL HIGHLIGHTS
- --------------------

29.  COMMENT:  In the  preamble  to the  financial  highlights,  the  disclosure
     currently states that "The total returns shown below do not include charges
     and expenses  imposed at the Separate  Account  Level." Add disclosure that
     states that if they did, the performance shown would have been lower.

     RESPONSE: The Investment Company has made the requested change.


LEGAL PROCEEDINGS
- -----------------

30.  COMMENT:  In accordance with Item 5(a)(3) of Form N-1A,  describe any legal
     proceedings  to which the Investment  Company,  Adviser or Distributor is a
     party.

     RESPONSE:  No change  has been made in  response  to this  Comment  30. The
     Investment  Company  confirmed that there are no such legal  proceedings to
     disclose.



Mr. Sonny Oh
April 27, 2007
Page 9 of 11


STATEMENT OF ADDITIONAL INFORMATION
- -----------------------------------

31.  COMMENT:  Confirm  accuracy  and  consistency  in  defined  terms  for both
     Prospectus and Statement of Additional Information.

     RESPONSE:  The  Investment  Company has reviewed  defined terms used in the
     registration statement and has made appropriate revisions.

32.  COMMENT:  In accordance  with Item 11 of Form N-1A, for each fund,  confirm
     that disclosure regarding each investment strategy used has been included.

     RESPONSE:  The Investment  Company has reviewed the disclosure and has made
     revisions as appropriate.

33.  COMMENT:  In  accordance  with Item  12(a) of Form N-1A,  confirm  that the
     management   information  table  12(d)(i)  includes  all  of  the  required
     information  (i.e.  number  of  portfolios  in  fund  complex  overseen  by
     director.)

     RESPONSE:  The Investment  Company has reviewed the disclosure and has made
     revisions as appropriate.

34.  COMMENT:  In accordance  with Item 12(b)(2) of Form N-1A,  confirm that the
     disclosure   regarding  board  committees  includes  all  of  the  required
     information.

     RESPONSE:  The Investment  Company has reviewed the disclosure and has made
     revisions as appropriate.

35.  COMMENT:  In accordance  with Item 12(b)(4) of Form N-1A,  confirm that the
     disclosure  regarding board of director  ownership of equity securities has
     been included and appears in the correct format.

     RESPONSE:  The Investment  Company has reviewed the disclosure and has made
     revisions as appropriate.

36.  COMMENT:  In accordance with Item 18 of Form N-1A, confirm that the pricing
     disclosure   includes   information   regarding  pricing  with  respect  to
     fund-of-funds and purchase of ETFs.

     RESPONSE:  The Investment  Company has reviewed the disclosure and has made
     revisions as appropriate.



Mr. Sonny Oh
April 27, 2007
Page 10 of 11

37.  COMMENT:  In  accordance  with Item  20(b) of Form  N-1A,  if  appropriate,
     include disclosure regarding commissions and other compensation received by
     each affiliated broker.

     RESPONSE: No change was made in response to this Comment 37. The Investment
     Company  notes  that  the  section  entitled  PORTFOLIO   TRANSACTIONS  AND
     BROKERAGE  discloses  that the  Investment  Company paid no  commissions to
     affiliated brokers.

PART C

38.  COMMENT:  In accordance  with Item 23(i) of Form N-1A,  please confirm that
     legal  opinions  for Small Cap Growth Fund,  Small Cap Value Fund,  Mid Cap
     Value Fund,  International  Fund and the Retirement  Funds will be filed as
     exhibits to the registration statement.

     RESPONSE:  The Investment  Company has filed, as exhibits to Post-Effective
     Amendment No. 30, opinions relating to the legality of shares for Small Cap
     Growth Fund, Small Cap Value Fund, Mid Cap Value Fund,  International  Fund
     and the Retirement Funds.

39.  COMMENT:  In accordance with Item 24 of Form N-1A,  confirm that the Part C
     includes disclosure for Control Persons and Principal Holders.

     RESPONSE: The Investment Company has made the requested change.

40.  COMMENT:  In accordance with Item 28 of Form N-1A,  confirm that the Part C
     includes  disclosure  regarding  the location of the  Investment  Company's
     books and records.

     RESPONSE: The Investment Company has made the requested change.

MISCELLANEOUS

41.  COMMENT:  Provide a response letter in the form of EDGAR  correspondence in
     regard to the comments above regarding this post-effective amendment.

     RESPONSE: The Investment Company is filing this response letter in the form
     of  EDGAR   correspondence  with  Post-Effective   Amendment  No.  30.  The
     Investment   Company  notes  further  that  a  letter   providing   "Tandy"
     representations was filed with Post-Effective Amendment No. 29.



Mr. Sonny Oh
April 27, 2007
Page 11 of 11


                                    * * * * *


     We appreciate the opportunity to respond to your comments.  If you have any
further comments or questions regarding this filing,  please contact me at (212)
536-4024 or Thomas L. Martin at (212) 224-1562.

Sincerely,


/s/ Beth R. Kramer

Beth R. Kramer