A geographically stratified sample of Fellows and Junior Fellows of The American College of Obstetricians and Gynecologists (ACOG) responded to a questionnaire, describing the source, coverage, and cost of their professional liability insurance, and the effects this had on patterns of practice. Most physicians carry primary professional liability coverage, although 6% do not. The majority pay less than $8000/year for a wide variety of dollar coverages. Less than half of the surveyed obstetrician-gynecologists carry excess/umbrella liability insurance, and a majority pay less than $2000/year for this coverage. The liability problem has not had a substantial effect on restricting the number of obstetrician-gynecologists, but it has had a major effect on patterns of practice.