Characteristics of best and worst clinical teachers in medicine are described by a random sample of medical school faculty, residents, and third- and fourth-year students at the University of Washington. The responses were factor analyzed and examined to determine whether the ratings were systematically influenced by professional role, faculty department, and teaching method. Best clinical teachers are described as being enthusiastic, clear and well organized, and adept at interacting with students and residents. Worst clinical teachers lack these skills and are characterized by negative personal attributes. Using analysis of variance, the investigator found no significant differences in ratings on the three variables examined. Six of the seven hypothesized dimensions of clinical teaching were confirmed by factor analysis. The results are discussed in relation to faculty development and evaluation of clinical teaching.