This study documents the distribution of health problems managed by obstetric-gynecologic nurse-practitioners (OB-GYN NPs) and obstetrician-gynecologists in community-based ambulatory care settings, and examines the effects of provider group on the distribution of health problems. A proportional sampling technique was used in selecting a sample of 3,873 visits for analysis from a total of 5,889 patient visits made to three community-based clinics during an 18-week period from February to June, 1978. A Patient Encounter Form was devised to record basic encounter data and the health problems managed by providers. The International Classification of Diseases, 9th revision (ICD-9-CM) was used as the coding system. Results indicated: (1) in each clinic, the distributions of health problems based on the three-digit headings of ICD-9-CM differed significantly between the OB-GYN NPs and the obstetrician-gynecologists; (2) the distributions of frequently reported health problems were clinically similar for OB-GYN NPs and obstetrician-gynecologists; and (3) the distributions of health problems with V codes were clinically similar for the two provider groups. Data indicate the OB-GYN NP caseloads are similar to those of obstetrician-gynecologists in frequently managed health problems and in wellness emphases. Nurse-practitioners are appropriate collaborators with obstetrician-gynecologists in the provision of primary health care for women.