To evaluate the impact of the inter-physician communication on the effectiveness of consultations, consultations performed by general and subspecialty medical consultation services for one week both early and late in the academic year were prospectively evaluated. Physicians commonly requested consultations to get advice on diagnosis (56 percent), advice on management (37 percent), or assistance in arranging or performing a procedure or test (20 percent). Despite our very liberal definitions, the requesting physician and the consultant completely disagreed on both the reason for the consultation and the principal clinical issue in 22 (14 percent) of 156 consultations. Consultants were twice as likely as the requesting physicians to rate consultations as crucial for management (35 percent versus 18 percent, p = 0.001) because they gave significantly higher ratings when they and the requesting physicians did not agree on the reasons for consultation. Consultations ordered for very specific purposes, such as assistance in arranging or performing a test, were rated significantly higher by the requesting physicians. It was found that breakdowns in communication are not uncommon in the consultation process and may adversely affect patient care, cost effectiveness, and education.