This study compared the demographic and practice characteristics of physicians with and without obstetric malpractice experience. The sample consisted of 387 family physicians and 204 obstetricians in Washington state who were insured for obstetrics by a major malpractice carrier between January 1982 and June 1988. Fifty-three physicians (9%) had an obstetric malpractice claim during the study period. The approximate overall rate of obstetric malpractice claims was low: 0.32 per 1000 deliveries. The higher the total delivery volume (exposure), the greater the chance of having malpractice experience. Although physicians with practices of over 200 deliveries per year were more likely to have had malpractice experience, their risk of malpractice experience per delivery was lower than that of providers doing fewer than 200 deliveries per year. Our work suggests that insurers might consider basing obstetric malpractice premiums on numbers of deliveries rather than specialty.