A cell-based vaccine derived from prostate cancer with potential immunopotentiating and antineoplastic activities. Prostate cancer vaccine ONY-P1 is derived from three irradiated allogeneic prostate cancer cell lines that represent different stages of prostate cancer and express a broad range of prostate and prostate cancer antigens. Upon administration, this vaccine may stimulate a host immune response against prostate cancer cells; in the vaccination schedule, the first two vaccinations are co-administered with bacillus Calmette-Guerin (BCG) as an adjuvant.