This observational study, reprinted from the Journal of the American Medical Association, analyzes whether important gender differences exist in the quality of hospital care. Participants included a total of 11,242 patients 65 years or older who were hospitalized with one of four diseases: congestive heart failure, acute myocardial infarction, pneumonia, and cerebrovascular accident. Data were derived from the nationally representative sample used to study the quality of hospital care for Medicare patients before and after the implementation of the retrospective payment system. A hierarchical (nested) cluster sampling design was used to draw disease-specific samples of patients hospitalized in 1981, 1982, 1985 or 1986 in one of 297 acute care hospitals located in 30 areas within five states. Measures used were sickness at admission, process, use rates, length of stay, discharge status, discharge destination, and mortality. Results showed that sex differences in sickness at admission varied by disease. There was some evidence that women received worse process of care, but the difference was very small. The authors found that the in-hospital experiences of elderly men and women showed greater similarities than differences. The concern that sex bias enters into clinical decision making during hospitalization is eased, although not entirely eliminated.