A practical program to train family physicians in obstetric ultrasound was tested with 13 family physicians. Each physician completed 6.5 days of course work and ultrasound laboratory apprenticeship prior to beginning a clinical preceptorship of approximately 14 months' duration. During the clinical preceptorship the physicians performed ultrasound studies in their own offices. All studies were reviewed by a local consultant radiologist utilizing examination data sheets and videotapes. At the conclusion of the training program, the physicians took a combined practical and written proficiency examination administered by an independent sonographer. Eight physicians completed the training, performing during the preceptorship an average of 78 examinations. The rated performance of the physicians improved markedly over the course of the preceptorship. During the last segment of the preceptorship the radiologist preceptors rated 94 percent of the ultrasound studies as acceptable, compared with 79 percent rated acceptable at the beginning of the preceptorship. Seven of the eight physicians completing the protocol took the proficiency examination: all passed. This study can provide a blueprint for an individual family physician to design his own training, or it can guide an academic department of family medicine in developing and evaluating ultrasound training programs for residents and practicing physicians.