Repetitive hospitalizations are a major health problem in elderly patients with chronic disease, accounting for up to one fourth of all inpatient Medicare expenditures. Congestive heart failure, one of the most common indications for hospitalization in the elderly, is also associated with a high incidence of early rehospitalization, but variables identifying patients at increased risk and an analysis of potentially remediable factors contributing to readmission have not previously been reported. We prospectively evaluated 161 patients 70 years or older that had been hospitalized with documented congestive heart failure. Hospital mortality was 13% (n = 21). Among patients discharged alive, 66 (47%) were readmitted within 90 days. Recurrent heart failure was the most common cause for readmission, occurring in 38 patients (57%). Other cardiac disorders accounted for five readmissions (8%), and noncardiac illness led to readmission in 21 cases (32%). Factors predictive of an increased probability of readmission included a prior history of heart failure, four or more admissions within the preceding 8 years, and heart failure precipitated by an acute myocardial infarction or uncontrolled hypertension (all P less than .05). Using subjective criteria, 25 first readmissions (38%) were judged possibly preventable, and 10 (15%) were judged probably preventable. Factors contributing to preventable readmissions included noncompliance with medications (15%) or diet (18%), inadequate discharge planning (15%) or follow-up (20%), failed social support system (21%), and failure to seek medical attention promptly when symptoms recurred (20%). Thus, early rehospitalization in elderly patients with congestive heart failure may be preventable in up to 50% of cases, identification of high risk patients is possible shortly after admission, and further study of nonpharmacologic interventions designed to reduce readmission frequency is justified.