As part of an effort to examine the structure and content of our residency program in internal medicine, we assessed interns' activities on call to identify problems with workload scheduling, supervision, and learning. Eleven interns were observed continuously during a 34-hour on-call period. Interns averaged 5.6 hours at the bedside, with 57 minutes of that time under direct supervision of a resident or attending physician. Nearly half of new patient examinations continued after midnight despite a special night admission team that evaluated all patients admitted after 11 PM. The interns averaged 21 beeps per 30 hours. They slept an average of 2.5 hours with two interruptions. They read about their patients an average of 4 minutes during the 34-hour period. Most supervision was away from the bedside (82/139 minutes). Bedside supervision occurred predominantly during rounds (45/57 minutes). Attending physicians averaged only 12 minutes of bedside interaction with the intern. Many of these findings were unanticipated. Structural defects in the training program were defined and are being addressed. Other training programs should consider similar analyses before making fundamental changes.