U.S. 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



or



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



For the fiscal year ended June 30, 2012



Commission file number 1-32186

YM BIOSCIENCES INC.

(Exact name of registrant as specified in
its charter)



|Nova Scotia, Canada(Province or other jurisdiction of incorporation or organization) | 2836(Primary Standard Industrial
Classification Code Number (if applicable)) | Not applicable(I.R.S. Employer
Identification Number (if Applicable))
|------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------- | ---------------------------------------------------------------------



Suite 400, Building 11, 5045 Orbitor
Drive, Mississauga, Ontario, Canada L4W 4Y4
(905) 629-9761(Address and Telephone Number of Registrant’s Principal Executive Offices)



DL Services Inc., 701 Fifth Avenue, Suite
6100, Seattle, Washington 98104

(206) 903-5448

(Name, Address (Including Zip Code) and
Telephone Number
(Including Area Code) of Agent For Service in the United States)



Securities registered or to be registered
pursuant to Section 12(b) of the Act.



|Title of each classCommon Shares | Name of each exchange on which registeredNYSE MKT
|-------------------------------- | -------------------------------------------------



Securities registered or to be registered
pursuant to Section 12(g) of the Act. None



Securities for which there is a reporting
obligation pursuant to Section 15(d) of the Act. None



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: 157,546,793.



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



|Yes   ̈ | No   ̈
|------ | -----













FORM 40-F



Principal Documents



The following documents, filed as Exhibits 99.1 through 99.3
hereto, are hereby incorporated by reference into this Annual Report on Form 40-F of YM BioSciences Inc. (the “Company”):



| | (a) | Annual Information Form for the fiscal year ended June 30, 2012;
| | --- | ----------------------------------------------------------------



| | (b) | Management’s Discussion and Analysis of Financial Condition and Results of Operations for the fiscal year ended June
30, 2012; and
| | --- | ----------------------------------------------------------------------------------------------------------------------------------



| | (c) | Consolidated
Financial Statements for the fiscal year ended June 30, 2012, prepared in accordance with International Financial Reporting Standards
as issued by the International Accounting Standards Board.
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



1







ADDITIONAL DISCLOSURE



Certifications and Disclosure Regarding Controls and Procedures.



| | (a) | Certifications. See Exhibits 99.4, 99.5, 99.6 and 99.7 to this Annual Report on Form 40-F.
| | --- | ------------------------------------------------------------------------------------------



| | (b) | Disclosure Controls and Procedures. As of the end of the Company’s fiscal year ended
June 30, 2012, an evaluation of the effectiveness of the Company’s “disclosure controls and procedures” (as such
term is defined in Rules 13a-15(e) and 15d-15(e) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”))
was carried out by the Company’s management with the participation of the principal executive officer and principal financial
officer. Based upon that evaluation, the Company’s principal executive officer and principal financial officer have concluded
that as of the end of that fiscal year, the Company’s disclosure controls and procedures are effective to ensure that information
required to be disclosed by the Company in reports that it files or submits under the Exchange Act is (i) recorded, processed,
summarized and reported within the time periods specified in Securities and Exchange Commission rules and forms and (ii) accumulated
and communicated to the Company’s management, including its principal executive officer and principal financial officer,
to allow timely decisions regarding required disclosure.
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



It should be noted that while the Company’s
principal executive officer and principal financial officer believe that the Company’s disclosure controls and procedures
provide a reasonable level of assurance that they are effective, they do not expect that the Company’s disclosure controls
and procedures or internal control over financial reporting will prevent all errors and 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.



| | (c) | Management’s Annual Report on Internal Control Over Financial Reporting.
| | --- | ------------------------------------------------------------------------



The required disclosure is included in the “Management’s
Annual Report on Internal Control Over Financial Reporting”that accompanies the Company’s Consolidated Financial
Statements for the fiscal year ended June 30, 2012, filed as Exhibit 99.3 to this Annual Report on Form 40-F.



| | (d) | Attestation Report of the Registered Public Accounting Firm.
| | --- | ------------------------------------------------------------



The required disclosure is included
in the “Report of Independent Registered Public Accounting Firm”that accompanies the Company’s Consolidated
Financial Statements for the fiscal year ended June 30, 2012, filed as Exhibit 99.3 to this Annual Report on Form 40-F.



| | (e) | Changes in Internal Control Over Financial Reporting. During the fiscal year ended June 30, 2012, there were no changes
in the Company’s internal control over financial reporting that have materially affected, or are reasonably likely to materially
affect, the Company’s internal control over financial reporting.
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------





2







Notices Pursuant to Regulation BTR.



None.



Audit Committee Financial Expert.



The required disclosure is included under the heading “Directors
and Senior Management–Committees of the Board of Directors—Audit Committee” in the Company’s Annual Information
Form for the fiscal year ended June 30, 2012, filed as Exhibit 99.1 to this Annual Report on Form 40-F.



Code of Ethics.



On December 19, 2004, the Company adopted a “code of ethics”
(as that term is defined in Form 40-F) that applies to its principal executive officer, principal financial officer, principal
accounting officer or controller, and persons performing similar functions, and such code of ethics was amended on September 22,
2006 (such code of ethics, as amended, the “Code of Ethics”). The Code of Ethics was filed as Exhibit 99.9 to the Company’s
Annual Report on Form 40-F for the fiscal year ended June 30, 2011. In addition, the Company undertakes to provide to any person,
without charge, upon request, a copy of the Code of Ethics. Requests for such copies should be directed, either orally or in writing,
to: Secretary, Suite 400, Building 11, 5045 Orbitor Drive, Mississauga, Ontario, Canada L4W 4Y4, phone number (905) 629-9761.



Except as disclosed above, since the adoption of the Code of
Ethics there have not been any amendments to the Code of Ethics or waivers, including implicit waivers, from any provision of the
Code of Ethics.



Principal Accountant Fees
and Services.



The required disclosure is included under the heading “Audit
Fees” in the Company’s Annual Information Form for the fiscal year ended June 30, 2012, filed as Exhibit 99.1 to this
Annual Report on Form 40-F.



Pre-Approval Policies and
Procedures.



The required disclosure is included under the heading “Audit
Fees—Pre-Approval Policies and Procedures” in the Company’s Annual Information Form for the fiscal year ended
June 30, 2012, filed as Exhibit 99.1 to this Annual Report on Form 40-F.





3







Off-Balance Sheet Arrangements.



The Company fully consolidates a joint venture (CIMYM BioSciences
Inc.) in which the Company is considered the primary beneficiary; and as such, the Company has recognized 100% of the cost of operations
and cash flows of this entity.



In addition, the Company is party to certain licensing agreements
that require the Company to pay a proportion of any fees that the Company may receive from sublicensees in the future. As of June
30, 2012, nil amounts were owing and the amount of future fees thereon, if any, is not determinable.



The Company has entered into various contracts for clinical,
preclinical and other studies, none of which individually exceeds Cdn.$1,000,000, totalling an aggregate of Cdn.$11,046,952, of
which Cdn.$6,078,851 had been incurred as at June 30, 2012 and the remaining Cdn.$4,968,101 had yet to be incurred as of that date.
Any early termination penalties under these contracts cannot exceed the amount of the contract commitment.



On September 20, 2012, the noon rate of exchange, as reported
by the Bank of Canada, of United States dollars for one Canadian dollar was: Cdn.$1.00 = U.S.$0.9774.



Tabular Disclosure of Contractual
Obligations.



|($ 000’s Canadian)                  |        | Payment due by period   
|----------------------------------- | ------ | ------------------------
|Contractual Obligations             | Total  | Less than
        1 Year
|Office Lease – Mississauga, Ontario | 46,397 | 46,397                  



Identification of the Audit
Committee.



The registrant has a separately-designated standing audit committee
established in accordance with Section 3(a)(58)(A) of the Exchange Act. The members of the audit committee are: Thomas I. A. Allen,
Dr. Henry Friesen, Nicole Onetto and Tryon M. Williams.



Mine Safety Disclosure.



Not applicable.



NYSE MKT Statement of Governance Differences.



As a Canadian corporation listed on the NYSE MKT, the Company
is not required to comply with most of the NYSE MKT corporate governance standards, so long as the Company complies with Canadian
corporate governance practices. In order to claim such an exemption, however, the Company must disclose the significant differences
between its corporate governance practices and those required to be followed by U.S. domestic issuers under the NYSE MKT’s
corporate governance standards. The Company has included a description of such significant differences in corporate governance
practices on its website, which may be accessed at www.ymbiosciences.com.





4







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 Securities and Exchange Commission staff, and to
furnish promptly, when requested to do so by the Securities and ExchangeCommission 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 a Form
F-X in connection with the class of securities in relation to which the obligation to file this report arises.



Any change to the name or address of the
agent for service of process of the Company shall be communicated promptly to the Securities and Exchange Commission by an amendment
to the Form F-X referencing the file number of the relevant registration statement.



SIGNATURES



Pursuant to the requirements of the Exchange
Act, the registrant 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, thereunto duly authorized, on September 21, 2012.



| | YM BioSciences Inc.
| | -------------------
| |                    
| | By:                
| | Name:              
| | Title:             





5







EXHIBIT INDEX



|Exhibit | Description                                                                                                                  
|------- | -----------------------------------------------------------------------------------------------------------------------------
|        |                                                                                                                              
|99.1    | Annual Information Form for the fiscal year ended June 30, 2012                                                              
|        |                                                                                                                              
|99.2    | Management’s Discussion and Analysis of Financial Condition and Results of Operations for the fiscal year ended June 30, 2012
|        |                                                                                                                              
|99.3    | Consolidated Financial Statements for the fiscal year ended June 30, 2012                                                    
|        |                                                                                                                              
|99.4    | Certification of Chief Executive Officer pursuant to Rule 13a-14(a) or 15d-14 of the Securities Exchange Act of 1934         
|        |                                                                                                                              
|99.5    | Certification of Chief Financial Officer pursuant to Rule 13a-14(a) or 15d-14 of the Securities Exchange Act of 1934         
|        |                                                                                                                              
|99.6    | Certification of Chief Executive Officer pursuant to 18 U.S.C. Section 1350                                                  
|        |                                                                                                                              
|99.7    | Certification of Chief Financial Officer pursuant to 18 U.S.C. Section 1350                                                  
|        |                                                                                                                              
|99.8    | Consent of KPMG LLP                                                                                                          
|        |                                                                                                                              
|        |