Most U.S. physicians limit their care of medically indigent populations, rendering millions of patients underserved. Using survey data from a national sample of 669 allopathic and osteopathic physicians, this paper explores the professional, demographic, and attitudinal correlates of care of medically indigent (Medicaid and uninsured) patients. Separate bivariate and multivariate data analyses for allopathic and osteopathic physicians generate path models of the influences of physician characteristics on care of indigent patients. For both physician groups, professional characteristics such as practice type, location, medical specialty, and perceptions of the medical system shape care of indigent patients. Differential patterns of association emerge, with care provided by osteopathic physicians most significantly influenced by private practice, while medical specialty and employment in community clinics shapes indigent care provided by allopathic physicians. Results highlight the utility of comparative analyses in discerning the mechanisms through which professional characteristics influence indigent care by diverse health providers.