EXHIBIT 5.1

May 22, 2001

OnLine Power Supply, Inc.
8100 South Akron Street, Suite 308
Englewood, Colorado 80112

Re:  OnLine Power Supply, Inc.
     Form S-8 Registration Statement
     Stock Option Plan for Non-Executive Directors

Gentlemen:

     We have acted as counsel to OnLine Power Supply, Inc., a Nevada corporation
(the  "company") in  connection  with the  registration  on the  Securities  and
Exchange Commission's (the "SEC") Form S-8 (the "registration  statement") under
the  Securities  Act of 1933, of the future  issuance of an aggregate of 300,000
shares of common stock,  upon exercise of nonqualified  options issued and to be
issued under the company's  Stock Option Plan for  Non-Executive  Directors (the
"plan").

     We  provide  this  opinion  as  required  by  item 8 of Form  S-8 and  item
601(b)(5)(I) of the SEC's Regulation S-K.

     We have reviewed the company's  articles of  incorporation  and amendments,
bylaws,  and corporate  proceedings  taken in connection with the plan. Based on
that  review,  we are of the opinion  that if, as and when the shares are issued
and sold (and the consideration  therefor  received)  pursuant to options issued
under  the plan,  and in  accordance  with the  registration  statement  and the
requirements of Form S-8, such shares will be duly  authorized,  legally issued,
fully paid, and nonassessable shares of common stock of the company.

     This  opinion  letter is provided as of the date first  written  above.  We
disclaim  any  obligation  to  advise  you of  facts,  circumstances,  events or
developments  which  hereafter  may be  brought to our  attention  and which may
alter,  affect or modify the opinion  stated  herein.  Our opinion is  expressly
limited  to the  matters  set forth  above.  We render no  opinion,  whether  by
implication or otherwise,  as to any other matters relating to the company,  the
plan,  or the shares  issuable  on exercise  of the  options  addressed  in this
opinion and the registration  statement. No opinion is stated, and none is to be
inferred or implied, regarding matters within ERISA or comparable state laws.

                                            Very truly yours,

                                             /s/ Stephen E. Rounds

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