Author analyzed 154 cases of transabdominal ultrasonography of normal adults who had normal urinalysis, no complaint of symptoms related with urinary system and no evidence of prostate disease. The maximum anteroposterior, transverse and longitudinal diameters of prostate were measured. The weight of prostate was computed using the formula for the weitht of ellipsoid of prostate were measured. The weight of prostate was computed using the formula for the weitht of ellipsoid object (W=SGx4/3$pi$ xl.r2.r3, w; weight, SG; specific gravity about 1.05 gm/ml, r; radius of prostate in any dimension) The result were as follows; 1. The average sizes of prostate were 4.12 $pm$0.68cm in trasverse diameter, 3.46$pm$0.49cm in longitudinal diameter and 2.36$pm$0.40cm in AP diameter Transverse diameter was the longest and AP diameter was the shortest in all cases. 2. The average weight of prostate in each age groups were 19.25$pm$6.78gm in the 3rd decade, 16.64$pm$5.18gm in the 4th decade, 16.28$pm$5.31gm in the 5th decade, 22.31 $pm$6.95gm in the 6th decade and 23.06$pm$8.18gm in over the 7th decade. The average weight of prostate in groups more than 50 years of age were significantly greater than younger age groups (p<0.005). Total aberage weight was 18.96$pm$6.78gm. 3. the distribution of prostate weighing over 30gm in each groups were 14.29% (5/35) in the 3rd decade, 0% (0/34) in the 4th decade, 2.63% (1/38) in the 5th decade, 20% (6/30) in the 6th decade and 23.5% (4/17) in the 7th decade.