**Exhibit      99.4**

**CERTIFICATION        PURSUANT TO RULE 13a-14 OR 15d-14 OF THE **
**SECURITIES        **

**EXCHANGE        ACT OF 1934, AS ADOPTED PURSUANT TO **
**SECTION        302 OF THE **

**SARBANES-OXLEY        ACT OF 2002**

| 1. | I                  have reviewed this annual report on Form 40-F of YM BioSciences                  Inc.; |
|----|-----------------------------------------------------------------------------------------------------------|

| 2. | Based                  on my knowledge, this report does not contain any untrue statement                  of a                  material fact or omit to state a material fact necessary to make                  the                  statements made, in light of the circumstances under which such                  statements                  were made, not misleading with respect to the period covered by                  this                  report; |
|----|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 3. | Based                  on my knowledge, the financial statements, and other financial                  information                  included in this report, fairly present in all material respects                  the                  financial condition, results of operations and cash flows of the                  issuer as                  of, and for, the periods presented in this                  report; |
|----|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 4. | The                  issuer’s other certifying officer and I are responsible for establishing                  and maintaining disclosure controls and procedures (as defined                  in Exchange                  Act Rules 13a-15(e) and 15d-15(e)) for the issuer and                  have: |
|----|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | (a) | Designed                  such disclosure controls and procedures, or caused such disclosure                  controls and procedures to be designed under our supervision, to                  ensure                  that material information relating to the issuer, including its                  consolidated subsidiaries, is made known to us by others within                  those                  entities, particularly during the period in which this report is                  being                  prepared; |
|--------|-----|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | (b) | Evaluated                  the effectiveness of the issuer’s disclosure controls and procedures and                  presented in this report our conclusions about the effectiveness                  of the                  disclosure controls and procedures, as of the end of the period                  covered by                  this report based on such evaluation;                  and |
|--------|-----|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | (c) | Disclosed                  in this report any change in the issuer’s internal control over financial                  reporting that occurred during the period covered by the annual                  report                  that has materially affected, or is reasonably likely to materially                  affect, the issuer’s internal control over financial reporting;                  and |
|--------|-----|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 5. | The                  issuer’s other certifying officer and I have disclosed, based on our most                  recent evaluation of internal control over financial reporting,                  to the                  issuer’s auditors and the audit committee of the issuer’s board of                  directors (or persons performing the equivalent                  function): |
|----|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | (a) | All                  significant deficiencies and material weaknesses in the design                  or                  operation of internal control over financial reporting which are                  reasonably likely to adversely affect the issuer’s ability to record,                  process, summarize and report financial information;                  and |
|--------|-----|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | (b) | Any                  fraud, whether or not material, that involves management or other                  employees who have a significant role in the issuer’s internal control                  over financial reporting. |
|--------|-----|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| Dated: September                  21, 2006 |                                                                                    |                                  |
|-------------------------------------------------|-----------------------------------------------------------------------------------------|---------------------------------------|
|                                            |                                                                                    |
|                                       |                                                                               |                             |
|                                            |                                                                                    | /s/                  David G.P. Allan |
|                                            | David                  G.P. Allan                                                       |
|                                            | Chief                  Executive Officer (Principal Executive                  Officer) |