PURPOSE: Burdizzo clamp ablation of the testes (CAT) may provide an incisionless, cost-effective form of androgen deprivation therapy (ADT) in men with adenocarcinoma of the prostate (ACP) who find bilateral orchiectomy (BO) unacceptable or can not afford medical ADT. The aim of this study was to compare CAT with BO as primary ADT in men with ACP. MATERIALS AND METHODS: Written, informed consent was obtained from men with locally advanced or metastatic ACP. Patients were prospectively randomized to BO (n = 9) or CAT (n = 10) under local anaesthesia, and were evaluated 3 and 7 days, 6 weeks and 3 months post-procedure. The protocol was approved by the local institutional ethics committee. Statistical analysis was performed using Student's, Mann-Whitney's and Fisher's tests. RESULTS: Mean duration of the procedure was significantly longer for BO than CAT (16.9 vs. 10.9 minutes). Mean pain scores during and after the procedure did not differ significantly. Serum testosterone decreased significantly on days 3 and 7 after CAT, but increased at 6 weeks, and was significantly higher than after BO. Serum luteinizing hormone increased significantly from day 3 after BO and from day 7 after CAT. Serum prostate specific antigen decreased significantly after BO, but not after CAT. Minor complications were more common after BO (89%) than CAT (40%). In the 9 men who did not achieve castrate levels of testosterone after CAT, BO was performed. CONCLUSIONS: CAT was quicker to perform and had a lower complication rate, but was not as effective as BO in achieving castrate serum testosterone levels.