Patients' satisfaction with the communicative aspects of their medical visits and understanding of their prescription drug regimens were measured for a sample of visits to a prepaid medical plan in a mid-Atlantic metropolitan area. The 1367 patients, who visited either the Department of Adult Medicine or the Urgent Care Center during a 2-week period and their physicians completed questionnaires as part of an ongoing quality assessment study. A 50% random sample of these patients was interviewed by telephone a week after their visits. Compliance was found to be positively correlated with understanding of drug instructions but negatively correlated with satisfaction with communication during the visit. Our findings suggest that satisfying doctor-patient interactions do not necessarily reflect effective communication about drug regimens.