CD10, a transmembrane endopeptidase, has been shown to be lost as an early event in prostate cancer. We aimed at evaluating the pattern of expression of CD10 in various Gleason’s grades of prostatic adenocarcinoma in comparison with nodular hyperplasia of prostate. This retrospective study included 30 cases of nodular hyperplasia and 30 of prostatic adenocarcinoma of various Gleason’s grades. Immunohistochemical staining for CD10 was performed on all cases and positivity evaluated as percentage of cells as well as location (membranous or cytoplasmic or both). Of prostatic adenocarcinomas, grade 3 was seen in 10 foci, grade 4 in 28 and grade 5 in 22 foci. CD10 positivity in carcinoma was lower than in nodular hyperplasia, with the lowest positivity in grade 5. The pattern of expression of CD10 also changed from membranous in grade 3 to cytoplasmic in grade 5. Loss of CD10 expression appears to be associated with increasing tumour grade in carcinoma prostate and this can potentially be useful in stratification of such patients.