[en] PSA ELISA kit was developed and compared to a commercial PSA ELISA kit (Cobas Registered trade mark Core PSA EIA, Roche Switzerland) with a correlation of 98.9% (r 0.989, p < 0.05). The precision of the assay kit evaluated by intermal quality control studies shown that the coefficient of variation of high, medium and low control were 4.4, 3.6 and 4.7% respectively. The sentuvity of detection was 0.25 ng/ml. This PSA ELISA kit has been used for detection of PSA in serum of 571 patients ages between 25-93 years old with satisfactory results. The normal range of PSA is 0 - 3.46 ng/ml (X-bar = 2SD, n = 384). The mean value of PSA in Prostate carcinoma before treatment and after successful treatment are 77.30 ng/ml (n = 53) and 1.64 ng/ml (n = 25) and increase to 53.71 ng/ml (n = 8) in metastasis. In Benign Prostate Hyperplasia (BPH) the range of PSA is 0 - 27.52 ng/ml (n = 74). Phi (φ) coefficient analysis shown that the correlation of PSA and Prostate carcinoma is 63.8% with a sensitivity and specificity of 100% and 86.9% respectively