Author analyzed 154 cases of transabdominal ultrasonography of normal adults who had normal urinalysis, nocomplaint of symptoms related with urinary system and no evidence of prostate disease. The maximumanteroposterior, transverse and longitudinal diameters of prostate were measured. The weight of prostate was computed using the formular for the weight of ellipsoid object (W=SGx4/3 pie r1.r2.r3, w; weight, SG; specificgravity about 1.05 gm/ml, r; radious of prostate in any dimension). The results were as follows; 1. The averagesized of prostate were 4.12±0.68 cm in transverse diameter, 3.46±0.49 cm in longitudinal diameter and 2.36±0.40cm in AP diameter. Transeverse diameter was the longest and AP diameter was the shorteset in all cases. 2. Theaverage weight of prostate in each age groups were 19.25±6.78 gm in the 3rd decade, 16.64±5.18 gm in the 4thdecade, 16.28±5.31 gm in the 5th decade, 22.31±6.95gm in the 6th decade and 13.06±8.18 gm in over the 7thdecade. The average weight of prostate in groups more than 50 years of age were significantly greater than youngerage groups (p<0.005). Total average weight was 18.96±6.78 gm. 3. The distribution of prostate weighting 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.