[en] Purpose: To evaluate the efficacy and toxicity of intermittent hormonal therapy in the treatment of residual/recurrent prostate cancer. Materials and Methods: Seventeen patients with biochemical evidence of residual/recurrent prostate cancer were initially treated with radiation therapy (RT)(13), neo-adjuvant hormonal therapy and RT (3), or RT following prostatectomy (1). The mean follow-up time was 19.4 months from the initiation of hormonal therapy. Hormonal therapy consisted of an LH-RH agonist alone (7), an anti-androgen alone (1) or a combination of both (9). Hormonal therapy was continued until the prostatic specific antigen (PSA) level became undetectable. IHT was reinstituted when the PSA reached a pre-determined level, usually greater than or equal to 10ng/ml. Results: The mean time from completion of primary treatment to the initiation of hormonal therapy was 32.5 months. The mean PSA at the start of the first cycle of hormonal therapy was 43.9ng/ml, the second cycle, 11.9ng/ml and the third cycle, 24ng/ml. The mean PSA levels at the end of the first and second cycle of hormonal therapy were .48 and .42ng/ml, respectively. No patient has yet completed the third cycle of hormonal therapy. The average duration of hormonal therapy was 10 months for the first cycle and 4 months for the second cycle. The mean intermittent time off hormones were 9.3 months between cycles 1 and 2, and 10 months between cycles 2 and 3. No patient has yet become refractory to hormonal therapy. Currently all patients are alive. All patients experienced hot flashes and decreased libido at varying degrees during treatment. Thirty-five percent experienced gynecomastia. During the intervals between hormonal therapy, most patients reported a decrease in hot flashes. Conclusion: This analysis supplies preliminary evidence that intermittent hormonal therapy is a viable option in patients with biochemical evidence of disease following initial therapy. It is associated with less treatment time, lower cost, fewer side effects and possibly improved quality of life. Whether IHT will prolong the duration of response remains to be determined