C-erbB-2 and HER-2/neu are identical genes isolated from three different sources simultaneously by investigators using different techniques. Both amplification and overexpression of C-erbB-2 have been associated with the progression and possible prognosis of a number of human cancers. In prostate, a similar predictive role has been hindered by variable immunohistochemical results. The aim of this work is to study the expression of C-erb B-2 in some benign and malignant prostatic lesions, evaluate the difference in its expression between these two study groups and to compare this oncogene expression in prostatic adenocarcinoma with other prognostic factors like grade and stage of the disease.