UNITED
STATES


SECURITIES
AND EXCHANGE COMMISSION


WASHINGTON,
D.C. 20549










FORM
40-F










(Check
One)


☐
Registration
statement pursuant to Section 12 of the Securities Exchange Act of
1934





☒
Annual
report pursuant to Section 13(a) or 15(d) of the Securities
Exchange Act of 1934





For the
fiscal year ended: December 31, 2018

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)





1100
– 40 University Avenue, Toronto, Ontario M5J 1T1 Canada;
Phone number: 416-979-1991


(Address and telephone number of registrant’s principal
executive offices)





C T
Corporation System


111 Eighth
Avenue


13th
Floor


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
Shares 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:





☒Annual Information
Form

☒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: 589,175,086 Common
Shares as at December 31, 2018.





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.





Yes  ☐            No 
 ☒





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  ☒            No 
 ☐





Indicate by check mark
whether the registrant is an emerging growth company as defined in
Rule 12b-2 of the Exchange Act.





Emerging growth
company  ☐





If an emerging growth company
that prepares its financial statements in accordance with U.S.
GAAP, indicate by check mark if the registrant has elected not to
use the extended transition period for complying with any new or
revised financial accounting standards† provided pursuant to
Section 13(a) of the Exchange Act.





Yes  ☐            No 
 ☐
















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, which are deemed filed
herewith.





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 and 99.7 through 99.21, 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, 2018 (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. Under Industry
Guide 7 standards, a “final” feasibility study is
required to report reserves, the three-year historical average
price is used in any reserve or cash flow analysis to designate
reserves and the primary environmental analysis or report must be
filed with the appropriate governmental authority.  Denison
has not prepared a feasibility study for the purposes of NI 43-101
or the requirements of the SEC in connection with its probable
mineral reserves disclosure, and therefore such mineral reserve
disclosure is not comparable to information from U.S. companies
subject to the reporting and disclosure requirements of the
SEC.





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, and investors are cautioned not to assume
that all or any part of an inferred mineral resource exists or is
economically or legally mineable. 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.





CURRENCY





Unless otherwise indicated,
all dollar amounts in this Annual Report on Form 40-F are in
Canadian dollars. The daily exchange rate published by the Bank of
Canada for the exchange of Canadian dollars into United States
dollars on December 31, 2018, the last business day of calendar
2018, was CDN$1.00 = US$0.7330.





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 SEC. 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, 2018 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 will prevent or detect all errors and all fraud. It
should be noted that 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 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 as issued by the
International Accounting Standards Board (the “IFRS”) .





A company’s internal
control over financial reporting includes those policies and
procedures that (i) pertain to the maintenance of records that, in
reasonable detail, accurately and fairly reflect the transactions
and dispositions of the assets of the company; (ii) provide
reasonable assurance that transactions are recorded as necessary to
permit preparation of financial statements in accordance with
generally accepted accounting principles, and that receipts and
expenditures of the company are being made only in accordance with
authorizations of management and directors of the company; and
(iii) provide reasonable assurance regarding prevention or timely
detection of unauthorized acquisition, use, or disposition of the
company’s assets that could have a material effect on the
financial statements.





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,
2018, the Company’s internal control over financial reporting
is effective.





It should be noted that a
control system, no matter how well conceived or operated, can only
provide reasonable, not absolute, assurance that the objectives of
the control system are met. The Company will continue to
periodically review its internal control over financial reporting
and may make such modifications from time to time as it considers
necessary.











C.
Report of
the Independent Registered Public Accounting
Firm





The effectiveness of the
Registrant’s internal control over financial reporting as of
December 31, 2018 has been audited by PricewaterhouseCoopers LLP,
an Independent Registered Public Accounting Firm, 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 on Form 40-F 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 American LLC (the “NYSE American”) and additionally
complies as necessary with the rules and guidelines of the NYSE
American 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
American.





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 Ms.
Patricia Volker) 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:





Member
Name

Education
& experience relevant to
performance
of audit committee dutiesCatherine J.G.
Stefan,
Chair of the
Audit
Committee

●

Chartered Professional
Accountant (Chartered Accountant)●

B.Comm●

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).








Brian D. Edgar

●

Law
degree, with extensive corporate finance experience●

Held
positions in a public company of Chairman since 2011 and President
and Chief Executive Officer from 2005 to 2011.●

Has
served on audit committees of a number of public
companiesPatricia M.
Volker

●

Chartered Professional
Accountant, Chartered Accountant, Certified Management
Accountant●

Over
17 years of service at the Chartered Professional Accountants of
Ontario, the self-regulating body for Ontario’s
CPAs●

Has
served and chaired audit committees of a number of
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 in the absence of such
designation, or affect the duties, obligations or liability of any
other member of the Audit Committee or Board.





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
www.denisonmines.com. In the fiscal year ended December 31, 2018,
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, 2018, 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, 2018 and 2017. Services
were billed and paid in Canadian dollars and the table below
reflects amounts in Canadian dollars.





Periods
Ending
Audit Fees(1)
Audit Related Fees (2)
Tax Fees (3)
All Other Fees(4)December
31, 2018
$171,434
$123,994
$0
$0December
31, 2017
$173,526
$115,212
$0
$0





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.








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:





2017
2018Audit
Related Fees:
100%
100%Tax
Fees:
100%
100%All Other
Fees:
100%
100%








OFF-BALANCE
SHEET ARRANGEMENTS





The Company does not have any
off-balance sheet arrangements at December 31, 2018 and at the date
hereof.





TABULAR
DISCLOSURE OF CONTRACTUAL OBLIGATIONS





At December 31, 2018, the
Company had a reclamation liability of $30,064,000, consisting of
$17,205,000 for Elliot Lake obligations, $12,837,000 for the
McClean Lake and Midwest joint ventures obligations and $22,000 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, 2018, the
balance in the trust fund was $3,120,000. In addition, the Company
has pledged as collateral $9,135,000 of cash to support its standby
letters of credit from the Bank of Nova Scotia for the McClean and
Midwest reclamation obligations.





In addition, the
Company’s contractual obligations at December 31, 2018 are as
follows:





(in
thousands of dollars)
Total
1
Year
2-3
Years
4-5
Years
After 5
YearsOperating
leases and other commitments
1,259,000
319,000
517,000
229,000
194,000





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, Mr. Brian D.
Edgar and Ms. Patricia M. Volker.  For further information on
these members, see “Audit Committee Financial Experts”
above.











INTERACTIVE
DATA FILE





An interactive data file has
been filed with the Consolidated Audited Financial Statements for
the Years Ended December 31, 2018 and 2017 on the Company’s
Form 6-K furnished to the Commission on March 8, 2019.





NYSE
AMERICAN CORPORATE GOVERNANCE





The Company’s common
shares are listed on the NYSE American. Section 110 of the NYSE
American Company Guide permits the NYSE American to consider the
laws, customs and practices of foreign issuers in relaxing certain
NYSE American listing criteria, and to grant exemptions from the
NYSE American 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 American standards is as
follows:





Board Composition: The NYSE American
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 American
Company Guide (the “NSYE
American Independence Standard”). The Company’s
Board is currently composed of nine members, six of whom qualify as
independent under the NYSE American Company Guide and who meet the
NSYE American Independence Standard, namely Mses. Stefan and Volker
and Messrs. Dengler, Edgar, Hochstein and Rand. Denison’s
remaining three directors do not satisfy the NYSE American
Independence Standard, being Messrs. Cates, Lundin and
Park.





Shareholder Meeting Quorum Requirement:
The NYSE American 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 American 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.





Shareholder Approval Requirements: The
NYSE American 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 American
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 American
shareholder approval requirement should a dilutive securities
issuance trigger such NYSE American shareholder approval
requirement in circumstances where such securities issuance does
not trigger a shareholder approval requirement under the rules of
the TSX.











Compensation Committee Requirements:
The NYSE American Company Guide requires that additional
independence criteria be applied to each member of the Compensation
Committee. The NYSE American Company Guide also mandates that the
Compensation Committee must have the authority to hire compensation
consultants, independent legal counsel and other compensation
advisors and exercise the sole responsibility to oversee the work
of any compensation advisors retained to advise the Compensation
Committee. In addition, before engaging a compensation advisor, the
Compensation Committee must consider at least six factors that
could potentially impact compensation advisor independence. The
Company follows Canadian Securities Administrators and TSX
requirements for Compensation Committee charters, independence and
authority. The Compensation Committee's Charter includes a
requirement that each member of the Compensation Committee be
independent and that the Compensation Committee have the authority
to retain outside advisors and determine the extent of funding
necessary for payment of consultants.





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 American corporate
governance requirements on specific transactions under Section 110
of the NYSE American 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 on Form 40-F.





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.











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 on Form 40-F to be signed on its behalf by the
undersigned, thereto duly authorized.





Registrant: DENISON MINES CORP.By:

/s/ David
D. CatesTitle:

President and Chief Executive
OfficerDate:

March 13, 2019














EXHIBIT
INDEX





99.1

Annual
Information Form for the Year Ended December 31,
201899.2

Management’s Discussion
and Analysis of Results of Operations and Financial Condition for
the Year ended December 31, 2018 (incorporated by reference to
Exhibit 99.3 of the Registrant’s Form 6-K furnished to the
Commission on March 8, 2019)99.3

Consolidated
Audited Financial Statements for the Years Ended December 31, 2018
and 2017 together with the Management's Report on Internal Control
over Financial Reporting and the report of our Independent
Registered Public Accounting Firm thereon (incorporated by
reference to Exhibit 99.2 of the Registrant’s Form 6-K
furnished to the Commission on March 8, 2019)99.4

Consent of
PricewaterhouseCoopers LLP99.5

Officers’
Certifications Required by Rule 13a-14(a) or Rule 15d-14(a) of the
Securities Exchange Act of 193499.6

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 Code99.7

Consent of Roscoe Postle
Associates Inc.99.8

Consent of Richard E. Routledge,
M.Sc., P.Geo.99.9

Consent of SRK Consulting
(Canada) Inc.99.10

Consent of Mark Liskowich,
P.Geo.99.11

Consent of Oy Leuangthong,
P.Eng.99.12

Consent of Cliff Revering,
P.Eng.99.13

Consent of G. David Keller,
P.Geo.99.14

Consent of SGS
Geostat99.15

Consent of
Allan Armitage,
Ph.D., P.Geo.99.16

Consent of GeoVector
Management Inc.99.17

Consent of
Alan Sexton,
M.Sc., P.Geo.99.18

Consent of Dale Verran,
M.Sc., P.Geo, Pr.Sci.Nat.99.19

Consent of Chad Sorba,
P.Geo.99.20

Consent of Serdar Donmez, P.Geo.,
E.I.T.99.21

Consent of Paul Burry,
P.Geo.101

Interactive Data Files with
respect to the Consolidated Audited Financial Statements for the
Years Ended December 31, 2018 and 2017 (incorporated by reference
to Exhibit 101 of the Registrant's Form 6-K furnished to the
Commission on March 8, 2019)