In view of the relatively high cost and mortality associated with hospitalization, 1,989 inpatients of family physicians and internists were compared with regard to length of stay, charges generated, charges generated per day, disposition (home, death, or other), number and type of diagnoses, and number of procedures. There were no interspecialty differences in mean length of stay (9 days), charges generated ($3,604), charges per day ($475), number of procedures done or disposition (79% went home, 9.5% died, and 11.5% had other placements). There were interspecialty differences in the type of diagnoses coded (chi-square = 52,P< 0.0001); family physicians tended to assign fewer diagnoses than internists (mean 3.08 versus 3.43,P< 0.0001). Review of a random sample of 50 charts of patients admitted to family physicians and a matched sample of charts of patients admitted to internists did not reveal any differences in either severity of illness on admission or rate of readmission. Multivariate adjustment for differences in case mix did not affect the direction or significance of the main findings. Similar findings were obtained whether using the hospital admission or the physician as the unit of analysis. The results are discussed in the context of related investigations in the ambulatory setting.