The absence of curative therapies for advanced or recurrent forms of prostate cancer has prompted a vigorous search for novel treatment strategies. Immunotherapy encompasses one particularly promising systemic approach to treat prostate cancer. Immune-based strategies to treat prostate cancer have recently been facilitated by the identification of a number of prostate tissue/tumor antigens that can be targeted, either by antibody or T cells, to promote prostate tumor cell injury or death. These same prostate antigens can also be used for the construction of vaccines to induce prostate-specific T cell-mediated immunity. Greater insight into specific mechanisms that govern antigen-specific T cell activation has brought with it a number of innovative methods to induce and enhance T cell-mediated responses against prostate tumors. For instance, autologous dendritic cells loaded with prostate antigens have proved useful to induce prostate-specific T cell activation. Similarly, in vivo manipulations of the T cell costimulatory pathway receptors can greatly facilitate tumor-specific T cell activation and potentiate T cell-mediated responses against a number of malignancies, including prostate cancer. Therefore, in this review we summarize recent advances pertaining to immunotherapeutic approaches to treat prostate cancer.