Improved Medical Decision Incentive Act of 2009

Authorizes any such provider or specialty group to bring a civil action in an appropriate U.S. district court to enjoin efforts by any health insurer to challenge or delay payment for services provided by the provider or a member of the specialty group in accordance with such best practices.

Amends titles XVIII (Medicare) and XIX (Medicaid) to provide for implementation of differential rates of payment for covered items and services (except those in a clinical trial or study or, in exceptional circumstances, requiring non-standard care) that favor treatment consistent with qualifying best practices approved under the Medicare and Medicaid programs.

Requires the Secretary of Health and Human Services, acting through the Administrator of the Centers for Medicare & Medicaid Services, to review annually and report to Congress on the efficacy of all qualifying best practices approved pursuant to this Act and, if applicable, any national best practices adopted pursuant to this Act.

Requires the Secretary also to host an annual conference on best practices for all state health directors, any state medical societies and medical specialty groups that have filed best practices for state approval, and any health insurers and advocacy groups that have participated in any administrative proceeding to approve best practices.