Obstetric practice among family physicians has declined in recent years. This study compared the practice patterns of family physicians and obstetrician-gynecologists with and without obstetric practices to provide objective information on one potential reason for this decline--the impact of obstetrics on physician lifestyle.In 2004, we surveyed all obstetrician-gynecologists, all rural family physicians, and a random sample of urban family physicians identified from professional association lists (N =2,564) about demographics, practice characteristics, and obstetric practices.A total of 1,197 physicians (46.7%) overall responded to the survey (41.5% of urban family physicians, 54.7% of rural family physicians, and 55.0% of obstetrician-gynecologists). After exclusions, 991 were included in the final data set. Twenty-seven percent of urban family physicians, 46% of rural family physicians, and 79% of obstetrician-gynecologists practiced obstetrics. The mean number of total professional hours worked per week was greater with obstetric practice than without for rural family physicians (55.4 vs 50.2, P=.005) and for obstetrician-gynecologists (58.3 vs 43.5, P = .000), but not for urban family physicians (47.8 vs 49.5, P = .27). For all 3 groups, physicians practicing obstetrics were more likely to provide inpatient care and take call than physicians not practicing obstetrics. Large proportions of family physicians, but not obstetrician-gynecologists, took their own call for obstetrics. Concerns about the litigation environment and personal issues were the most frequent reasons for stopping obstetric practice.Practicing obstetrics is associated with an increased workload for family physicians. Organizing practices to decrease the impact on lifestyle may support family physicians in practicing obstetrics.