Exhibit 10.20

                               RELEASE AGREEMENT

This Release Agreement (the "Agreement") is hereby entered into by and between
Cognos Corporation (the "Company") and Terry Hall ("Employee" or "you"), for
good and sufficient consideration as more fully described below, that:

  1. Employment Status. Your employment with the Company ceased as of December
10, 2003 (the "Termination Date"). Your regular salary also ceased as of the
Termination Date. You will be paid for any earned but unused vacation days as
of that date. Any entitlement you had or might have had under any Company-
provided benefit plan, incentive program or practice terminated on the
Termination Date, except as required by federal or state law or as otherwise
described below.

  2. Mutual Release.

      (a) Employee Release. In exchange for the consideration described herein,
which is in addition to anything of value to which you are already entitled,
and other good and valuable consideration, the sufficiency of which is hereby
acknowledged, you, on behalf of yourself and your representatives, agents,
estate, heirs, successors and assigns, absolutely and unconditionally hereby
release, remise and forever discharge the Company Releasees (defined as the
Company, its parent(s), affiliates, divisions, subsidiaries, successors and
assigns, and its and their respective shareholders, officers, directors,
employees, agents, representatives, and attorneys, in both their individual
and official capacities) from any and all actions or causes of action,
charges, suits, claims, complaints, obligations, contracts, liabilities,
agreements, promises, debts and damages, of any kind or nature whatsoever,
whether existing or contingent, known or unknown, suspected or unsuspected, in
law or in equity, which arise out of, and/or are related to, your employment
with or separation from employment with the Company. You agree that this
Release is all-encompassing and shall act as a full and total release of any
claims that you have, may have, or ever had against the Company Releasees from
the beginning of the world to the Effective Date of this Agreement, including,
but not limited to, claims under any federal, state or local constitution,
statute, ordinance, bylaw or regulation dealing with either employment or
employment discrimination such as those laws or regulations concerning
discrimination on the basis of age, race, color, creed, religion, sex, sexual
harassment, sexual orientation, national origin, ancestry, marital status,
pregnancy, childbirth or related medical conditions, disability, veteran
status, military service or application for military service; any contract,
whether oral or written, express or implied; any tort; and any common law.

      (b) You further agree to release and discharge the Company Releasees from
any and all claims which might be made by any other person or organization on
your behalf, and you specifically waive any right to become, and promise not
to become, a member of any class in a case in which a claim or claims against
the Company are made involving any matters subject to release pursuant to
Section 2(a).

      (c) Company Release. In exchange for the Employee Release contained in
this Section 2, the Company and its parent(s), affiliates, divisions,
subsidiaries, successors and assigns absolutely and unconditionally hereby
release, remise and forever discharge you and your representatives, agents,
estate, heirs, successors and assigns from any and all actions or causes of
action, charges, suits, claims, complaints, obligations, contracts,
liabilities, agreements, promises, debts and damages, of any kind or nature
whatsoever, whether existing or contingent, known or unknown, suspected or
unsuspected, in law or in equity, from the beginning of the world to the
Effective Date of this Agreement, which arise out of your employment with or
separation from employment with the Company. Notwithstanding the foregoing,
the Company may bring an action to enforce the terms of your Employment
Agreement, dated December 3, 2001.

  3. Waiver of Rights and Claims Under the Age Discrimination in Employment
     Act of 1967.

Since you are 40 years of age or older, you have been informed that you have
or might have specific rights and/or claims under the Age Discrimination in
Employment Act of 1967 ("ADEA") and you agree that:

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      (a) In consideration of the Company Release described in Section 2
hereof, which is in addition to anything of value to which you already may be
entitled, you specifically waive such rights and/or claims to the extent that
such rights and/or claims arose prior to or on the date this Agreement was
executed;

      (b) You understand that rights or claims under the ADEA that may arise
after the date this Agreement is executed are not waived by you;

      (c) You hereby are and were advised of your right to consult with your
counsel of choice prior to executing this Agreement and you acknowledge that
you have not been subject to any undue or improper influence interfering with
the exercise of your free will in executing this Agreement;

      (d) You have carefully read and fully understand all of the provisions of
this Agreement, and you knowingly and voluntarily agree to all of the terms
set forth in this Agreement;

      (e) In entering into this Agreement, you are not relying on any
representation, promise or inducement made by the Company or its attorneys
with the exception of those promises described in this document;

      (f) When the Company presented you with this Agreement, you were informed
that you have at least 21 days to review this Agreement and consider its terms
before signing it; and

      (g) The 21-day period will not be affected or extended by any revisions,
whether material or immaterial, that might be made to this Agreement.

  4. Proprietary and Company Materials. By Termination Date, you will return to
the Company all proprietary and Company information and materials, including
but not limited to, documents, financial reports, memoranda, sales brochures,
manuals, building keys and passes, courtesy parking passes, names and
addresses of all Company customers and potential customers, customer lists,
customer contacts, customer information and/or data, sales information,
diskettes, intangible information stored on diskettes, business or marketing
plans, reports, projections, software programs and data compiled with the use
of those programs, tangible copies of trade secrets and confidential
information, and any and all other information or property previously or
currently held or used by you that is or was related to your employment with
the Company. You agree that in the event that you discover any other Company
or proprietary materials in your possession after the Termination Date, you
will immediately return such materials to the Company.

  5. Non-Disparagement and Confidentiality. You agree not to misappropriate,
divulge or communicate, directly or indirectly, any confidential and/or
proprietary information, including trade secret information, of the Company or
any third party associated with the Company. You further agree not to
disparage the business, operations, technologies, products, services,
marketing strategies, pricing policies, management, affairs and financial
condition of the Company. You also agree that you shall not divulge or
publish, directly or indirectly, any information whatsoever regarding the
substance, terms or existence of this Agreement and/or any discussions or
negotiations relating to this Agreement, to any person or organization other
than your attorneys, accountants, financial advisors or members of your
immediate family or persons at the Company with the Company's permission.
Nothing herein shall prohibit or bar you from providing truthful testimony in
any legal proceeding or in communicating with any governmental agency or
representative or from making any truthful disclosure required, authorized or
permitted under law; provided however, that in providing such testimony or
making such disclosures or communications, you will use your best efforts to
ensure that this Section is complied with to the maximum extent possible.

  6. Representations.

      (a) This Agreement represents the complete and sole understanding between
the parties concerning the subject matter hereof, and supersedes any and all
other agreements and understandings, whether oral or written, concerning the
subject matter hereof; provided that [the Employment Agreement between you and
the Company, dated December 3, 2001, shall remain in effect pursuant to its
respective terms. Nothing in this Agreement shall bar or prohibit you from
contacting, seeking assistance from or participating in any proceeding

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before any federal or state administrative agency to the extent permitted by
applicable federal, state and/or local law. However, notwithstanding this
provision, you will be prohibited to the fullest extent authorized by law from
obtaining monetary damages in any agency proceeding in which you do so
participate.

      (b) This Agreement may not be modified, altered or rescinded except upon
written consent of the Company and you. If any provision of this Agreement, or
part thereof, is held invalid, void or voidable as against the public policy
or otherwise, the invalidity shall not affect other provisions, or parts
thereof, which may be given effect without the invalid provision or part. To
this extent, the provisions, and parts thereof, of this Agreement are declared
to be severable. Moreover, if one or more of the provisions contained in this
Agreement shall for any reason be held to be excessively broad as to scope,
activity, subject or otherwise so as to be unenforceable at law, such
provision or provisions shall be construed by the appropriate judicial body by
limiting or reducing it or them, so as to be enforceable to the maximum extent
compatible with the applicable law as it shall then appear. Any waiver of any
provision of this Agreement shall not constitute a waiver of any other
provision of this Agreement unless expressly so indicated otherwise.

      (c) You may not assign any of your rights or delegate any of your duties
under this Agreement. The rights and obligations of the Company under this
Agreement shall inure to the benefit of the successors and assigns of the
Company.

  7. Effective Date. For a period of seven (7) days following your execution of
this Agreement, you may revoke the Agreement and the Agreement shall not
become effective or enforceable until the revocation period has expired.

  8. Counterparts. This Agreement may be executed in any number of counterparts,
each of which shall be deemed to be an original, but all of which together
shall constitute one and the same instrument.

YOU REPRESENT THAT YOU HAVE READ THE FOREGOING AGREEMENT, FULLY UNDERSTAND THE
TERMS AND CONDITIONS OF SUCH AGREEMENT, AND ARE VOLUNTARILY EXECUTING THE
SAME. IN ENTERING INTO THIS AGREEMENT, YOU DO NOT RELY ON ANY REPRESENTATION,
PROMISE OR INDUCEMENT MADE BY THE COMPANY, WITH THE EXCEPTION OF THE
CONSIDERATION DESCRIBED IN THIS DOCUMENT.

- -------------------------------        -------------------------------
Terry Hall                             Cognos Corporation
                                       By:
                                       Title:

Dated: ________________________        Dated: ________________________

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                        Waiver of 21-Day Review Period

I, Terry Hall, acknowledge that I was informed and understand that I have 21
days within which to consider the attached Release Agreement, have had the
opportunity to consult with an attorney regarding such Agreement and have
considered carefully every provision of the Agreement, and that after having
engaged in those actions, I prefer to and have requested that I enter into the
Agreement prior to the expiration of the 21-day period.

Dated: ________________________        -------------------------------
                                       Terry Hall

Dated: ________________________        -------------------------------
                                       Witness

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