Activities performed by pharmacists and technicians in an ambulatory care pharmacy were evaluated by work sampling to determine circumstances in which pharmacist time was used ineffectively. Over a two-week period, pharmacists and technicians in the outpatient pharmacy at University of Utah Hospitals and Clinics recorded their activities at random intervals during the workday. The data were analyzed by using descriptive statistics and an institution-specific index of pharmacist efficiency. During the study, 1565 pharmacist observations and 1465 technician observations of work activities were collected. Pharmacists spent 50% of their shifts on clinical and professional activities, while technicians spent 50% of their shifts processing prescriptions and 30% of their shifts directly supporting pharmacists clinical and professional activities. The efficiency with which pharmacists used the available work time for patient care was 56% (100% would mean that they spent all available work time on patient care activities). During a shift, 2.3 minutes per prescription per pharmacist was available for professional and clinical activities. Self-reported work sampling enabled the ambulatory care pharmacy staff to identify staff use of time.