PURPOSE: We studied the need for hospital care of patients 74 years old or younger with clinically localized prostate cancer managed by deferred endocrine therapy. MATERIALS AND METHODS: Our series included all cases of newly diagnosed, clinically localized prostate cancer reported to the Danish Cancer Registry from 1977 to 1992. Information on the number of hospitalizations and operations performed from 1977 to 1994 was obtained from the Danish Hospital Discharge Registry. RESULTS: Our study included 4,790 men 37 to 74 years old with clinically localized prostate cancer. During the year of diagnosis and once a year of the following 9 years patients were hospitalized an average of 2.2 and 1 times and remained hospitalized an average of 22 and 10 days, and prostate cancer accounted for approximately 80% and 67% of hospitalizations the year of diagnosis and once a year subsequently. Nearly 90% of patients underwent transurethral prostatic resection within the year of diagnosis and in 30% repeat resection was necessary. A third of the patients underwent orchiectomy during the study period. Median time from the diagnosis to orchiectomy was 23 months. The estimated probability of surviving 5 and 10 years without orchiectomy was 39% and 17%, respectively. CONCLUSIONS: Patients diagnosed with clinically localized prostate cancer managed expectantly had a substantial need for hospital care in the years after the diagnosis. When evaluating outcome and quality of life after treatment of localized prostate cancer, the cost and impact of associated morbidity must be considered as well as patient survival.