The experience of serving as an expert witness can add considerably to a physician's knowledge of medicine and the forces that affect the profession. Each case compels the physician to examine carefully all the clinical data. The physician must assess the quality of care given and render an opinion that is consistent with the facts and pertinent literature. He must defend his position under close questioning by an informed attorney aided by expert witnesses on the opposing side. This rigorous exercise requires considerable skill and experience. It has many of the characteristics of a well-conducted clinicopathological conference, with the added drama of the interplay of personalities. Despite the stimulating atmosphere, it is critical to maintain objectivity by asking yourself repeatedly, "What would I have done if placed in the same circumstance as the accused physician?" If you accept the responsibility of serving as an expert witness, it should be one of the best consultations you have ever given.