EXHIBIT
31.1





SECTION
302 CERTIFICATION





I, Daniel
T. MacInnis, certify that:





1. I have
reviewed this annual report on Form 40-F of MAG Silver Corp.;





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)) and internal control over financial reporting (as
defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) 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)
Designed such internal control over financial reporting, or caused such internal
control over financial reporting to be designed under our supervision, to
provide reasonable assurance regarding the reliability of financial reporting
and the preparation of financial statements for external purposes in accordance
with generally accepted accounting principles;





(c)
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





(d)
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 functions):





(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.





Date:
March 27, 2008


/s/ “Daniel
T. MacInnis”


Daniel T.
MacInnis


Chief
Executive Officer