We describe a detailed, cross-sectional, self-report time study of laboratory physician tasks in a regionalized, multisite academic setting, using custom data collection templates programmed into personal digital assistants (PDAs). The 7-week study was completed by 56 medical and scientific staff (86% participation rate). Participants recorded 12,781 PDA entries of specific tasks completed during the study period. The mean number of entries per worked day per participant was 8.14 (range, 1.96-14.33). Study results demonstrated that professional staff worked, on average, 53.5 hours per week. Percentage work time spent in each activity area was as follows: clinical, direct, 50.6%; administration, 18.5%; clinical, indirect, 9.5%; research, 8.2%; learning/continuing education, 5.3%; teaching, 4.9%; and quality assurance, 3.1%. These percentages varied significantly by laboratory medicine subspecialty and by type of academic appointment. The findings confirm that activities not directly involved with patient care, such as administration, quality assurance, teaching, research, and professional development, typically occupy 40% to 50% of a laboratory physician's time.