Hypoxia is common in prostate tumours, promoting tumour progression and impairing treatment responses. Hypoxia stimulates angiogenesis but blood vessels formed in tumours are functionally abnormal so the tissue remains hypoxic. Castration treatment is the standard therapy for advanced prostate cancer. In non-malignant prostate tissue castration-induced epithelial cell death is in part mediated by vascular insult and acute hypoxia, but in prostate tumours the cell death response is less prominent and the tumours will eventually relapse. The effect of androgen ablation therapy should therefore be enhanced by additional targeting of the vasculature and hypoxic tumour cells. However if castration fails to kill a sufficiently large number of cells it could by inducing hypoxia make the situation worse. Androgen ablation treatment, may, after the initial vascular insult, result in temporary vascular normalisation and transiently increased tissue oxygen levels. During this time window, which needs to be better defined, the efficacy of cytotoxic drug and radiation treatments are probably enhanced. In order to allow development of more effective treatment strategies for advanced prostate cancer we need to understand the role of hypoxia in prostate cancer progression and treatment responses. With this knowledge we can properly tailor and time additional treatments with androgen ablation.