POWER OF ATTORNEY





 The undersigned hereby constitutes and appoints Laurence L. Betterley,

James E. Flaherty, Robert K. Ranum and John R. Remakel, or any one of them

acting alone, the undersigned's true and lawful attorney-in-fact and agent with

full power of substitution and resubstitution, for the undersigned and in the

undersigned's name, place and stead, in any and all capacities, to sign any or

all Forms 3, 4 or Form 5 relating to beneficial ownership of securities of

Cardiovascular Systems, Inc. (the "Issuer"), to file the same, with all

exhibits thereto and other documents in connection therewith, with the

Securities and Exchange Commission and to deliver a copy of the same to the

Issuer, granting unto said attorney-in-fact and agent full power and authority

to do and perform each and every act and thing requisite and necessary to be

done in and about the premises, as fully to all intents and purposes as the

undersigned might or could do in person, hereby ratifying and confirming all

said attorney-in-fact and agent, or his substitute or substitutes, may lawfully

do or cause to be done by virtue thereof.  The undersigned acknowledges that

the foregoing attorney-in-fact, in serving in such capacity at the request of

the undersigned, is not assuming any of the undersigned's responsibilities to

comply with Section 16 of the Securities Exchange Act of 1934.



 This Power of Attorney shall remain in effect until such time as the

undersigned is no longer subject to the provisions of Section 16 of the

Securities Exchange Act of 1934 with respect to securities of the Issuer.



 The undersigned hereby indemnifies the attorneys-in-fact for all losses

and costs the attorneys-in-fact may incur in connection with or arising from

the attorneys-in-fact's execution of their authorities granted hereunder.



 IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to

be executed as of this 25th day February, 2009.







       /s/ David L. Martin

       David L. Martin