transrectal sonography of prostate was sensitive to textural changes produced by both benign prostate hyperplasia (BPH) and prostate cancers. During recent 4 years twenty cases of BPH and twenty cases of pro-state cancers proven histologically were analyzed in thier sonographic features retrospectively by using tran-srectal postate sonography and suprapubic prostate sonography. The results were as follows : 1. Mean weights of BPH revealed isoechogenecity in 11 cases homogeneity 18 cases well defined capsular margins in 19 cases and calcification in 16 cases. 3. Sonographic features of prostate cancers recvealed mixed echogenecity in 14 cases inhomogeneity in 15 cases poorly defined capsular margin in 14 cases and calcifications in 13 cases. 4. Authors concluded that prostate sonography were valuable diagnostic modality in the dirrerentiation of BPH and prostate cancers.