Endocrine treatment (ET) has in the past been shown to be beneficial in delaying clinical progression in all stages of prostate cancer, leading to an improvement of progression free survival in virtually all trials ever conducted. The first observations on this issue date back to the studies of the Veterans Administration Cooperative Urological Research Group in the 1960s. The period of time during which ET and the resulting side effects can be avoided is strongly dependent on the clinical stage of the disease. This treatment period is long in men who have minimal disease, such as a rising prostate-specific antigen after potentially curative management; however, it is considerably shorter in men who initially present with metastatic disease. In these situations, the potential benefit in quality of life, and avoidance of adverse events must be matched against the benefit in terms of gaining progression free time for the individual patient. This difficult task is supported by information supplied in this review. Locally advanced and regional (lymph node positive; stage T3N0-1M0Gx) disease is the domain of adjuvant ET. In this field, important progress has recently been made due to trials, which combine aggressive treatment of the primary tumor with adjuvant ET initiated at the same time. Therefore, in locally advanced and regional disease, radiotherapy or surgery combined with adjuvant ET must be considered state-of-the-art.