We report a rare case of metastatic prostate adenocarcinoma to the pituitary gland. The patient had lung and bone metastases when he presented with bitemporal hemianopsia. He was also receiving total androgen blockade at that time. Magnetic resonance imaging showed an intrasellar mass, and biopsy confirmed metastatic prostate cancer. Radiotherapy, in the form of intensity-modulated radiotherapy, was delivered to the intrasellar mass. The patient responded well to radiotherapy. The mechanisms of spread to the pituitary gland and treatment options, including intensity-modulated radiotherapy, are discussed.