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UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWASHINGTON, D.C.
20549

FORM 40-F

(Check One)

[   ]
    Registration statement pursuant to Section 12
      of the Securities Exchange Act of 1934[X]
    Annual report pursuant to Section 13(a) or
      15(d) of the Securities Exchange Act of 1934


|For the fiscal year ended: December 31, 2014 | Commission file number: 001-33414
|-------------------------------------------- | ---------------------------------

DENISON MINES CORP.(Exact name of
registrant as specified in its charter)

Ontario, Canada(Province or other jurisdiction of
incorporation or organization)

1090(Primary standard industrial classification code
number)

98-0622284(I.R.S. employer identification number)

Atrium on Bay, 595 Bay Street, Suite 402, Toronto, Ontario
M5G 2C2; Phone number: 416-979-1991(Address and telephone number of
registrants principal executive offices)

CT Corporation System 111
Eighth Avenue 13thFloor New York, NY 10011 Phone
number: 212-894-8800

(Name, address and telephone number of agent for service in the
United States)

Securities registered pursuant to Section 12(b) of the Act:
Not applicable.

Securities registered pursuant to Section 12(g) of the Act:
Common Stock without par value.

Securities for which there is a reporting obligation pursuant
to Section 15(d) of the Act: Not applicable.

For annual reports, indicate by check mark the information
filed with this form:

| | [X] | Annual Information Form | [X] | Audited Annual Financial Statements
| | --- | ----------------------- | --- | -----------------------------------

Indicate the number of outstanding shares of each of the
issuers classes of capital or common stock as of the close of the period
covered by the annual report: 505,868,894 Common Shares

Indicate by check mark whether the registrant by filing the
information contained in this form is also thereby furnishing the information to
the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of
1934 (the Exchange Act). If Yes is marked, indicate the file number assigned
to the registrant in connection with such rule.

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Yes [   ]                                      No [X]

Indicate by check mark whether the registrant: (1) has filed
all reports required to be filed by Section 13(d) or 15(d) of the Exchange Act
during the preceding 12 months (or for such shorter period that the registrant
has been required to file such reports); and (2) has been subject to such filing
requirements in the past 90 days.

Yes [X]                                       No [   ]

Indicate by check mark whether the registrant has submitted
electronically and posted on its corporate Web site, if any, every Interactive
Data File required to be submitted and posted pursuant to Rule 405 of Regulation
S-T (232.405 of this chapter) during the preceding 12 months (or for such
shorter period that the Registrant was required to submit and post such files).
Not applicable

Yes [   ]                                       No [   ]

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DOCUMENTS FILED PURSUANT TO GENERAL INSTRUCTIONS

In accordance with General Instruction B.(3) of Form 40-F,
Denison Mines Corp. (the Company or the Registrant) hereby
incorporates by reference Exhibits 99.1 through 99.3 as set forth in the Exhibit
Index attached hereto.

In accordance with General Instruction D.(9) of Form 40-F, the
Company has filed written consents of certain experts named in the foregoing
Exhibits as Exhibits 99.4 through 99.23, as set forth in the Exhibit Index
attached hereto.

FORWARD-LOOKING STATEMENTS

Certain of the information contained in this Annual Report on
Form 40-F, including the documents incorporated herein by reference, may contain
forward-looking information. Forward-looking information and statements may
include, among others, statements regarding the future plans, costs, objectives
or performance of the Company, or the assumptions underlying any of the
foregoing. In this Annual Report on Form 40-F, words such as may, would,
could, will, likely, believe, expect, anticipate, intend, plan,
estimate and similar words and the negative form thereof are used to identify
forward-looking statements. Forward-looking statements should not be read as
guarantees of future performance or results, and will not necessarily be
accurate indications of whether, or the times at or by which, such future
performance will be achieved. Forward-looking statements and information are
based on information available at the time and/or managements good-faith belief
with respect to future events and are subject to known or unknown risks,
uncertainties and other unpredictable factors, many of which are beyond the
Companys control. These risks, uncertainties and assumptions include, but are
not limited to, those described under the section Risk Factors in the
Companys Annual Information Form for the fiscal year ended December 31, 2014
(the AIF), which is filed as Exhibit 99.3 to this Annual Report on Form
40-F, and could cause actual events or results to differ materially from those
projected in any forward-looking statements.

The Companys forward-looking statements contained in the
exhibits incorporated by reference into this Annual Report on Form 40-F are made
as of the respective dates set forth in such exhibits. In preparing this Annual
Report on Form 40-F, the Company has not updated such forward-looking statements
to reflect any subsequent information, events or circumstances or otherwise, or
any change in managements beliefs, expectations or opinions that may have
occurred prior to the date hereof, nor does the Company assume any obligation to
update such forward-looking statements in the future, except as required by
applicable laws.

RESOURCE AND RESERVE ESTIMATES

The terms mineral reserve, proven mineral reserve and
probable mineral reserve are Canadian mining terms as defined in accordance
with National Instrument 43-101  Standards of Disclosure for Mineral Projects
(NI 43-101), which references the guidelines set out in the Canadian
Institute of Mining, Metallurgy and Petroleum (the CIM) Standards on
Mineral Resources and Mineral Reserves, adopted by the CIM council, as may be
amended from time to time by the CIM. These definitions differ from the
definitions in Industry Guide 7 (Industry Guide 7) under the United
States Securities Act of 1933, as amended. Under Industry Guide 7,
mineralization may not be classified as a reserve unless the determination has
been made that the mineralization could be economically and legally produced or
extracted at the time of the reserve determination.

In addition, the terms mineral resource, measured mineral
resource, indicated mineral resource and inferred mineral resource are
defined in and required to be disclosed by NI 43-101; however, these terms are
not defined terms under Industry Guide 7 and normally are not permitted to be
used in reports and registration statements filed with the Securities and
Exchange Commission (the SEC or the Commission). Investors are
cautioned not to assume that any part or all of mineral deposits in these
categories will ever be converted into reserves. Inferred mineral resources
have a great amount of uncertainty as to their existence, and great uncertainty
as to their economic and legal feasibility. It cannot be assumed that all or any
part of an inferred mineral resource will ever be upgraded to a higher category.
Under Canadian rules, estimates of inferred mineral resources may not form the
basis of feasibility or pre-feasibility studies, except in rare cases.

Accordingly, information contained in this Annual Report on
Form 40-F and the documents incorporated by reference herein containing
descriptions of the Companys mineral deposits may not be comparable to similar
information made public by U.S. companies subject to the reporting and
disclosure requirements under the United States federal securities laws and the
rules and regulations thereunder.

3

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CURRENCY

Unless otherwise indicated, all dollar amounts in this Annual
Report on Form 40-F are in United States dollars. The exchange rate of Canadian
dollars into United States dollars, on December 31, 2014, based upon the noon
buying rate payable in Canadian dollars as certified for customs purposes by the
Bank of Canada, was U.S. $1.00 = CDN$1.1601.

TAX MATTERS

Purchasing, holding, or disposing of securities of the
Registrant may have tax consequences under the laws of the United States and
Canada that are not described in this Annual Report on Form 40-F.

DISCLOSURE CONTROLS AND PROCEDURES

A. Evaluation of Disclosure Controls and Procedures

The Company maintains disclosure controls and procedures to
ensure that information required to be disclosed in the Companys filings under
the Securities Exchange Act of 1934, as amended (the Exchange Act), is
recorded, processed, summarized and reported in accordance with the requirements
specified in the rules and forms of the Securities and Exchange Commission (the
SEC or the Commission). The Company carried out an evaluation,
under the supervision and with the participation of its management, including
the Chief Executive Officer and Chief Financial Officer, of the effectiveness of
the design and operation of the Companys disclosure controls and procedures
(as defined in the Exchange Act Rule 13a-15(e)) as of the end of the period
covered by this report. Based upon that evaluation, the Chief Executive Officer
and Chief Financial Officer concluded that the Companys disclosure controls and
procedures as of December 31, 2014, are effective to ensure that information
required to be disclosed by the Registrant in reports it files or submits under
the Exchange Act is recorded, processed, summarized and reported within the time
periods specified in the SECs rules and forms and is accumulated and
communicated to the Registrants management, including its Chief Executive
Officer and Chief Financial Officer, as appropriate to allow timely decisions
regarding required disclosure.

The Companys disclosure controls and procedures are designed
to provide reasonable assurance of achieving their objectives and, as indicated
in the preceding paragraph, the Chief Executive Officer and Chief Financial
Officer believe that the Companys disclosure controls and procedures are
effective at that reasonable assurance level, although the Chief Executive
Officer and Chief Financial Officer do not expect that the disclosure controls
and procedures or internal control over financial reporting will prevent or
detect all errors and all fraud. A control system, no matter how well conceived
or operated, can provide only reasonable, not absolute, assurance that the
objectives of the control system are met. The Company will continue to
periodically review its disclosure controls and procedures and internal control
over financial reporting and may make such modifications from time to time as it
considers necessary.

B. Managements Annual Report on Internal Control Over
Financial Reporting

The Companys management is responsible for establishing and
maintaining an adequate system of internal control over financial reporting. Internal
control over financial reporting is a process designed to provide reasonable
assurance regarding the reliability of the Companys financial reporting and the
preparation of financial statements for external purposes in accordance with
International Financial Reporting Standards. Management conducted an assessment
of the Companys internal control over financial reporting based on the
framework established by the Committee of Sponsoring Organizations of the Treadway Commission on Internal Control  Integrated Framework
(2013). Based on this
assessment, management concluded that, as of December 31, 2014, the Companys
internal control over financial reporting is effective.

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C. Report of the Independent Auditor, PricewaterhouseCoopers LLP

The effectiveness of the Registrants internal control over
financial reporting as of December 31, 2014 has been audited by
PricewaterhouseCoopers LLP, an independent auditor, as
stated in their report included with the Registrants Audited Financial
Statements, which are an exhibit to this Annual Report on Form 40-F.

D. Changes in Internal Control Over Financial Reporting

There was no change in the Companys internal control over
financial reporting that occurred during the twelve month period covered by this
Annual Report that has materially affected, or is reasonably likely to
materially affect, the Companys internal control over financial reporting.

CORPORATE GOVERNANCE

The Company is listed on the Toronto Stock Exchange (the
TSX) and is required to describe its practices and policies with regard
to corporate governance with specific reference to the corporate governance
guidelines of the Canadian Securities Administrators on an annual basis by way
of a corporate governance statement contained in the Companys Annual
Information Form or Information Circular. The Company is also listed on the NYSE
MKT LLC (the NYSE MKT) and additionally complies as necessary with the
rules and guidelines of the NYSE MKT as well as the SEC. The Company reviews its
governance practices on an ongoing basis to ensure it is in compliance with the
applicable laws, rules and guidelines both in Canada and in the United States.

The Companys Board of Directors (the Board) is
responsible for the Companys corporate governance policies and has separately
designated a standing Corporate Governance and Nominating Committee. The Board
has determined that the members of the Corporate Governance and Nominating
Committee are independent, based on the criteria for independence and
unrelatedness prescribed by the Sarbanes-Oxley Act of 2002, Section 10A(m)(3),
and the NYSE MKT.

Corporate governance relates to the activities of the Board,
the members of which are elected by and are accountable to the shareholders, and
takes into account the role of the senior officers who are appointed by the
Board and who are charged with the day to day administration of the Company. The
Board is committed to sound corporate governance practices that are both in the
interest of its shareholders and contribute to effective and efficient decision
making.

BENEFIT PLAN BLACKOUT PERIODS

Not applicable.

AUDIT COMMITTEE FINANCIAL EXPERT

The Companys Board of Directors has determined that all three
members of its Audit Committee (Ms. Catherine Stefan, Mr. Brian D. Edgar and Mr.
William A. Rand) are audit committee financial experts, within the meaning of
paragraph 8(b) of General Instruction B of Form 40-F, and are also independent
within the meaning of United States and Canadian securities regulations and
applicable stock exchange requirements. A description of the education and
experience of these persons is set forth in the table below:

|            | Education & experience relevant to         
|----------- | -------------------------------------------
|Member Name | performance of audit committee
      duties

|Catherine J.G. Stefan, |  | Chartered Professional Accountant (Ontario)                                                                                                                                          
|---------------------- | - | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|Chair of the Audit     |  | B.Comm                                                                                                                                                                               
|Committee              |  | Held position of Chief Operating Officer of
      O&Y Properties Inc.,                                                                                                               
|                       |   | President of Stefan & Associates and
      Executive Vice-President of Bramalea Group, Chair, Tax Committee of the
      Canadian Institute of Public Real Estate Companies (CIPREC).
|                       |   |                                                                                                                                                                                      

5

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|Brian D. Edgar  |  | Law degree, with extensive corporate finance
      experience                                                                     
|--------------- | - | ----------------------------------------------------------------------------------------------------------------------------------
|                |  | Held positions of Chairman since 2011 and
      President and Chief Executive Officer of a public company from 2005 to
      2011.
|                |  | Has served on audit committees of a number of
      public companies                                                              
|                |   |                                                                                                                                   
|William A. Rand |  | B.Comm (Accounting)                                                                                                               
|                |  | Two law degrees, with extensive corporate
      finance experience                                                                
|                |  | Has served on audit committees of a number of
      public companies                                                              

Through such education and experience, each of these three
members has experience overseeing and assessing the performance of companies and
public accountants with respect to the preparation, auditing and evaluation of
financial statements, and has: (1) an understanding of generally accepted
accounting principles and financial statements; (2) the ability to assess the
general application of such principles in connection with the accounting for
estimates, accruals and reserves; (3) experience preparing, auditing, analyzing
or evaluating financial statements that present a breadth and level of
complexity of accounting issues that are generally comparable to the breadth and
complexity of issues that can reasonably be expected to be raised by the
Companys financial statements; (4) an understanding of internal control over
financial reporting; and (5) an understanding of audit committee functions.

The SEC has provided that the designation of an audit committee
financial expert does not make him or her an expert for any purpose, impose on
him or her any duties, obligations or liability that are greater than the
duties, obligations or liability imposed on him or her as a member of the Audit
Committee and the Board of Directors in the absence of such designation, or
affect the duties, obligations or liability of any other member of the Audit
Committee or Board of Directors.

CODE OF ETHICS

The Company has adopted a code of ethics that applies to the
Companys directors, officers and employees, including the Chief Executive
Officer, Chief Financial Officer, principal accounting officer or controller,
persons performing similar functions and other officers, directors and employees
of the Company. A current copy of the amended code of ethics is on the Companys
website at http://www.denisonmines.com. In the fiscal year ended December 31,
2014, the Company has not made any amendment to a provision of its code of
ethics that applies to any of its Chief Executive Officer, Chief Financial
Officer, principal accounting officer or controller or persons performing
similar functions that relates to one or more of the items set forth in
paragraph (9)(b) of General Instruction B to Form 40-F. In the fiscal year ended
December 31, 2014, the Company has not granted a waiver (including an implicit
waiver) from a provision of its code of ethics to any of its Chief Executive
Officer, Chief Financial Officer, principal accounting officer or controller or
persons performing similar functions that relates to one or more of the items
set forth in paragraph (9)(b) of General Instruction B to Form 40-F.

PRINCIPAL ACCOUNTANT FEES AND SERVICES

The following table discloses the fees billed to the Company by
its external auditor during the last two financial years ended December 31, 2014
and 2013. Services were billed and paid in Canadian dollars and have been
translated into U.S. dollars using an average CAD$/US$ annual exchange rate of
$1.1045 for 2014 and $1.0298 for 2013.

Periods
      
      Ending
    Audit Fees(1)
    Audit Related 
      Fees (2)
    Tax Fees (3)
    All Other Fees(4)December 31, 2013
    $295,401
    $121,134
    $0
    $123,373December 31, 2014
    $309,371
    $136,411
    $0
    $9,507


Notes:

|(1) | The aggregate fees billed for audit services of the
      Companys consolidated financial statements.                                                                                                                                                                                                                                                                                                                               
|--- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|(2) | The aggregate fees billed for assurance and related
      services that are reasonably related to the performance of the audit or
      review of the Companys financial statements and are not disclosed in the
      Audit Fees column. Fees relate to reviews of interim consolidated
      financial statements and specified audit procedures not included as part
      of the audit of the consolidated financial statements.
|(3) | The aggregate fees billed for tax compliance, tax advice,
      and tax planning services, such as transfer pricing and tax return
      preparation.                                                                                                                                                                                                                                                                                
|(4) | The aggregate fees billed for professional services other
      than those listed in the other three columns. For 2014, All Other Fees
      relates to the Companys acquisition of International Enexco Limited. For
      2013, All Other Fees relates to the Companys acquisitions of JNR
      Resources Inc., Fission Energy Corp. and Rockgate Capital
  Corp.                                                           

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The Companys audit committee mandate and charter provides that
the audit committee shall (i) approve, prior to the auditors audit, the
auditors audit plan (including, without limitation, staffing), the scope of the
auditors review and all related fees, and (ii) pre-approve any non-audit
services (including, without limitation, fees therefor) provided to the Company
or its subsidiaries by the auditor or any auditor of any such subsidiary and
shall consider whether these services are compatible with the auditors
independence, including, without limitation, the nature and scope of the
specific non-audit services to be performed and whether the audit process would
require the auditor to review any advice rendered by the auditor in connection
with the provision of non-audit services.

The following sets forth the percentage of services described
above that were approved by the audit committee pursuant to paragraph
(c)(7)(i)(C) of Rule 2-01 of Regulation S-X:

2013
    2014Audit Related Fees:
    100%
    100%Tax Fees:
    100%
    100%All Other Fees:
    100%
    100%


OFF-BALANCE SHEET ARRANGEMENTS

The Companys off-balance sheet arrangements at December 31,
2014 are as follows:

In connection with the Companys sale of its U.S. Mining
Division to Energy Fuels Inc (EFR) on June 29, 2012, the Company
remained a guarantor under a sales contract assigned to EFR. The sales contract
requires deliveries of 200,000 pounds of U3O8 per year from 2013 to 2017 at a
selling price of 95% of the long-term U3O8 price at the time of delivery. Should
EFR not be able to deliver for any reason other than force majeure as defined
under the contract, the Company may be liable to the customer for incremental
costs incurred to replace the contracted quantities if the unit price of the
replacement quantity is greater than the contracted unit price selling amount.
EFR has agreed to indemnify the Company for any future liabilities it may incur
related to this guarantee.

The Company has agreed to indemnify EFR in connection with
ongoing litigation between Denison Mines (USA) Corp (DUSA) (a company
acquired by EFR as part of the sale of the U.S. Mining Division) and a
contractor in respect of a construction project at the White Mesa mill. This
matter was heard before an arbitrator in November, 2013 and a decision in favour
of DUSA was granted in January 2014. The Company does not expect to recover a
material amount of damages related to this issue.

TABULAR DISCLOSURE OF CONTRACTUAL OBLIGATIONS

At December 31, 2014, the Company had a reclamation liability
of $17,659,000, consisting of $11,234,000 for Elliot Lake obligations,
$6,406,000 for the McClean Lake and Midwest joint ventures obligations and
$19,000 for  other obligations. The Company maintains a trust fund equal to
the estimated reclamation spending for the succeeding six calendar years, less
interest expected to accrue on the funds, in respect of its liability for Elliot
Lake. At December 31, 2014, the balance in the trust fund was $2,068,000.

In addition, the Companys contractual obligations at December
31, 2014 are as follows:

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After(in thousands)
    
    Total
    
    
    1 Year
    
    
    2-3
      Years
    
    
    4-5
      Years
    
    
    5
      YearsDebt Obligations
    $
    39
    
    
    30
    
    
    9
    
    
    -
    
    
    -Operating leaseand other
      obligations
    $
    473
    
    
    269
    
    
    186
    
    
    18
    
    
    -


IDENTIFICATION OF THE AUDIT COMMITTEE

The Company has a separately-designated standing audit
committee established in accordance with Section 3(a)(58)(A) of the Exchange
Act. The committee members are Ms. Catherine J. G. Stefan and Messrs. Brian D.
Edgar and William A. Rand. For further information on these members, see
discussion above under Audit Committee Financial Experts.

INTERACTIVE DATA FILE

An interactive data file is not yet required to be filed since
the Company prepares its financial statements in accordance with International
Financial Reporting Standards.

NYSE MKT CORPORATE GOVERNANCE

The Companys common shares are listed on the NYSE MKT. Section
110 of the NYSE MKT Company Guide permits the NYSE MKT to consider the laws,
customs and practices of foreign issuers in relaxing certain NYSE MKT listing
criteria, and to grant exemptions from the NYSE MKT listing criteria based on
these considerations. An issuer seeking relief under these provisions is
required to provide written certification from independent local counsel that
the non-complying practice is not prohibited by home country law. A description
of the significant ways in which the Companys governance practices differ from
those followed by domestic companies pursuant to the NYSE MKT standards is as
follows:

Board Composition: The NYSE MKT requires that a listed
company have a Board of Directors consisting of at least a majority of members
who satisfy applicable independence standards under Section 803 of the NYSE MKT
Company Guide (the NSYE MKT Independence Standard). The Companys Board
is currently composed of eight members, five of whom qualify as independent
under the NYSE MKT Company Guide and who meet
the NSYE MKT Independence Standard, namely Ms. Stefan and Messrs. Craig, Dengler, Edgar
and Rand. Denisons remaining three directors do not satisfy the NYSE MKT
Independence Standard, being Messrs.  Hochstein,  Lundin and Park.

Shareholder Meeting Quorum Requirement: The NYSE MKT
minimum quorum requirement for a shareholder meeting is one-third of the shares
issued and outstanding and entitled to vote for a meeting of a listed companys
shareholders. The TSX does not specify a quorum requirement for a meeting of a
listed companys shareholders. The Companys current required quorum at any
meeting of shareholders as set forth in the Companys by-laws is two persons
present, each being a shareholder entitled to vote at the meeting or a duly
appointed proxyholder for an absent shareholder so entitled, holding or
representing in aggregate not less than 10% of the shares of the Company
entitled to be voted at the meeting. The Companys current quorum requirement is
not prohibited by, and does not constitute a breach of, the Business
Corporations Act (Ontario) (the OBCA), applicable Canadian
securities laws or the rules and policies of the TSX.

Proxy Solicitation Requirement: The NYSE MKT requires
the solicitation of proxies and delivery of proxy statements for all shareholder
meetings of a listed company, and requires that these proxies be solicited
pursuant to a proxy statement that conforms to the proxy rules of the U.S.
Securities and Exchange Commission. The Company is a foreign private issuer as
defined in Rule 3b-4 under the Exchange Act, and the equity securities of the
Company are accordingly exempt from the proxy rules set forth in Sections 14(a),
14(b), 14(c) and 14(f) of the Exchange Act. The Company solicits proxies in
accordance with the OBCA, applicable Canadian securities laws and the rules and
policies of the TSX.

8

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Shareholder Approval Requirements: The NYSE MKT requires
a listed company to obtain the approval of its shareholders for certain types of
securities issuances. One is the sale of common shares (or securities
convertible into common shares) at a discount to officers or directors. The TSX
rules require shareholder approval for the issuance of shares to insiders in
private placements where insiders are being issued more than 10% of the
presently issued and outstanding shares. The NYSE MKT also requires shareholder
approval of private placements that may result in the issuance of common shares
(or securities convertible into common shares) equal to 20% or more of presently
outstanding shares for less than the greater of book or market value of the
shares. There is no such requirement under Ontario law. The TSX rules require
shareholder approval for private placements that materially affect control, or
where more than 25% of presently issued and outstanding shares will be issued at
a discount to market. The Company will seek a waiver from the NYSE MKT
shareholder approval requirement should a dilutive securities issuance trigger
such NYSE MKT shareholder approval requirement in circumstances where such
securities issuance does not trigger a shareholder approval requirement under
the rules of the TSX.

The foregoing are consistent with the laws, customs and
practices in Canada.

In addition, the Company may from time-to-time seek relief from the NYSE MKT corporate governance requirements on specific transactions under Section 110
of the NYSE MKT Company Guide by providing written certification from
independent local counsel that the non-complying practice is not prohibited by
its home country law, in which case, the Company shall make the disclosure of such
transactions available on its website at www.denisonmines.com. Information
contained on, or accessible through, our website is not part of this Annual
Report.

The Registrant has elected not to adopt Section 805(c) of the
NYSE MKT Company Guide applicable to charters and independence of Compensation
Committees of U.S. domestic issuers. As a foreign private issuer, the Registrant
is not required to comply with these rules.

MINE SAFETY DISCLOSURE

Not applicable.

UNDERTAKING AND CONSENT TO SERVICE OF PROCESS

A. Undertaking

The Company undertakes to make available, in person or by
telephone, representatives to respond to inquiries made by the Commission staff,
and to furnish promptly, when requested to do so by the Commission staff,
information relating to: the securities registered pursuant to Form 40-F; the
securities in relation to which the obligation to file an Annual Report on Form
40-F arises; or transactions in said securities.

B. Consent to Service of Process

The Company has previously filed with the SEC a Form F-X in
connection with its common stock. Any change to the name or address of the
Companys agent for service shall be communicated promptly to the SEC by
amendment to the Form F-X referencing the file number of the Company.

9

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SIGNATURES

Pursuant to the requirements of the Exchange Act, the Company
certifies that it meets all of the requirements for filing on Form 40-F and has
duly caused this Annual Report to be signed on its behalf by the undersigned,
thereto duly authorized.

Registrant: DENISON MINES CORP.

By: /s/ Ron F.
HochsteinTitle:  Chief Executive
Officer           
 
Date:  March 12,
2015

10

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EXHIBIT INDEX

|99.1  | Annual Information Form for the
      Year Ended December 31, 2014                                                                                                                                                                                        
|----- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|99.2  | Managements Discussion and Analysis of Results of
      Operations and Financial Condition for the Year ended December 31, 2014
      (Exhibit 99.3 of the Registrants Form 6-K furnished to the Commission on
      March 6, 2015)                     
|99.3  | Consolidated Audited Financial Statements for the Years
      Ended December 31, 2014 and 2013 (Exhibit 99.2 of the Registrants Form 6-K
      furnished to the Commission on March 6, 2015) together with the
      Independent Auditors Report thereon
|99.4  | Consent of PricewaterhouseCoopers LLP                                                                                                                                                                                                                     
|99.5  | Officers Certifications
      Required by Rule 13a-14(a) or Rule 15d-14(a) of the Securities Exchange
      Act of 1934                                                                                                                                  
|99.6  | Officers Certifications Required by Rule
      13a-14(b) or Rule 15d-14(b) and Section 1350 of Chapter 63 of Title 18 of
      the United States Code                                                                                                    
|99.7  | Consent of Roscoe Postle
      Associates Inc.                                                                                                                                                                                                            
|99.8  | Consent of Leo R. Hwozdyk,
      P.Eng.                                                                                                                                                                                                                   
|99.9  | Consent of Thomas C. Pool, P.E.                                                                                                                                                                                                                           
|99.10 | Consent of Richard E. Routledge, M.Sc., P.Geo.                                                                                                                                                                                                            
|99.11 | Consent of James W. Hendry,
      P.Eng.                                                                                                                                                                                                                  
|99.12 | Consent of Luke Evans, M.Sc., P.Eng.                                                                                                                                                                                                                      
|99.13 | Consent of Hrayr Agnerian,
      M.Sc. (Applied), P. Geo.                                                                                                                                                                                                 
|99.14 | Consent of William E. Roscoe, Ph.D., P.Eng.                                                                                                                                                                                                               
|99.15 | Consent of Geostat Systems
      International Inc.                                                                                                                                                                                                       
|99.16 | Consent of Michel Dagbert, P.Eng.                                                                                                                                                                                                                         
|99.17 | Consent of GeoVector Management
      Inc.                                                                                                                                                                                                                
|99.18 | Consent of Allan Armitage, Ph.D., P.Geol.                                                                                                                                                                                                                 
|99.19 | Consent of Alan Sexton, M.Sc.,
      P.Geol.                                                                                                                                                                                                              
|99.20 | Consent of CSA Global (UK) Ltd.                                                                                                                                                                                                                           
|99.21 | Consent of Malcolm Titley,
      B.Sc. (Geology and Chemistry), MAusIMM, MAIG                                                                                                                                                                             

11

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