Background: Pharmacists' scope of practice has been steadily expanding across Canada to encompass clinical activities. In January 2009, pharmacists in British Columbia (BC) were given the authority to adapt prescriptions for renewals; change in dose, formulation or regimen; and therapeutic substitutions. This study evaluated the labour costs associated with pharmacy adaptation services in BC. Methods: Ten high-adapting pharmacies participated in the study. Through workflow observations, we measured the time incurred for adapted and nonadapted prescriptions. Results: We observed 91 adapted prescriptions and 1081 nonadapted prescriptions. The total average time to provide adapted prescriptions was 6:43 minutes (SD 3:50) longer than to provide nonadapted prescriptions. The total average cost of an adapted prescription was $6.10 greater than a nonadapted prescription. Renewals took the least amount of time to complete, and therapeutic substitutions took the most time to complete. Discussion: Through workflow observations, it was determined that 10 stages of activity occur when adapting a prescription, with the most time being expended during the documentation and processing phases. Labour costs associated with adapted prescriptions were higher than for nonadapted prescriptions.