Prostate cancer is linked to the male sex hormone testosterone. In advanced disease, blocking the production of testosterone using androgen deprivation therapy causes regression of prostate cancer and minimises or prevents symptoms associated with the disease. Luteinising hormone-releasing hormone agonists are commonly used in the management of prostate cancer, however less is known about the role of the newer gonadotrophin-releasing hormone (GnRH) antagonists. This article focuses on the differences between the two treatments and provides nurses with the knowledge to explain the use of GnRH antagonists to patients and administer this therapy effectively.