The invention relates to methods for treating prostate cancer comprising administration of an anti-CTLA4 antibody, or an antigen-binding portion thereof, particularly a human antibody to human CTLA4, e.g., antibody 3.1.1, 4.1.1, 4.8.1, 4.10.2, 4.13.1, 4.14.3, 6.1.1, ticilimumab (also known as 11.2.1), 11.6.1, 11.7.1, 12.3.1.1, 12.9.1.1, and ipilimumab (also known as MDX-010 and 10D1), in combination with hormonal therapy. Hormonal therapy agents include, inter alia, an anti-androgen (e.g., megestrol, cyproterone, flutamide, nilutamide, and bicalutamide), a GnRH antagonist (e.g., abarelix and histrelin), and a LH-RH agonist (e.g., leuprolide, goserelin, and buserelin). The invention relates to neoadjuvant therapy, adjuvant therapy, therapy for rising PSA, first-line therapy, second-line therapy, and third-line therapy of prostate cancer, whether localized or metastasized.