Purpose. Results of a study comparing reimbursement for medication therapy management (MTM) services with a resource-based relative value scale (RBRVS) versus a time-based billing model are reported. Methods. Reimbursement claims for MTM services provided by a standalone clinic during a 6.5-year period were reviewed. Actual billing amounts calculated according to Minnesota's RBRVS for MTM services, which emphasizes case complexity as a determinant of payment rates, were compared with hypothetical billing amounts calculated using a strictly time-based method designed to more accurately capture the costs of providing MTM services. A paired t test was conducted to analyze differences in the billable amounts calculated via the two methods. Results. Reimbursement claims for a total of 525 face-to-face MTM encounters with 60 patients were analyzed. Using the RBRVS method, the mean ± S.D. billing amount per encounter was $83.71 ± $36.67; using the strictly time-based method, the mean ± S.D. billing amount was $111.83 ± $34.55 per encounter (mean difference, $28.12; p < 0.0001). These findings indicate that the use of time-based versus RBRVS-based billing methodology would have resulted in an additional $14,763 in MTM services reimbursement for the 525 evaluated encounters. Conclusion. The RBRVS-based method consistently resulted in a lower billing amount per encounter than the strictly time-based billing method, suggesting that reimbursement for MTM services may not be aligned with the actual costs of providing those services.