The primary objective of this study was to determine whether warfarin therapy monitoring by a pharmacist would benefit a long-term care facility, by maintaining patients within therapeutic INR range more consistently than the current practice of physician monitoring.Secondary objectives included whether adverse events resulting from non-therapeutic INR levels differed significantly between groups and whether pharmacist interventions resulted in decreased overall costs to the facility. A retrospective chart review was conducted on all patients treated with warfarin for a minimum of 14 days within a Long-Term Care (LTC) facility to compare Time within Therapeutic Range (TTR) between staff treated patients versus pharmacist treated patients. A total of 552 INRs were obtained for all patients during the study period: 499 (90.4%) under staff supervision and 53 (9.6%) under clinical pharmacist supervision. Of the 499 tests performed by the River Garden staff, 203 were within the desired range, compared with 29 of the 53 tests performed by the clinical pharmacist being in range. For the primary endpoint, a total of 1483 INRs were imputed, corresponding to the number of days between true INR measurements. INRs attributable to clinic staff management were within the therapeutic range 47.1% of the time, whereas INRs attributable to clinical pharmacist management were within the therapeutic range 58.7% of the time (P < 0.0001 for the comparison). Warfarin can be effectively monitored by a clinical pharmacist and routinely lead to appropriate INR levels in the nursing home setting, while potentially saving the facility healthcare dollars.