This study aimed to determine the penile size and its correlation with somatometric parameters in physically normal Iranian adult men. To do this, a random sample of 1500 normal men aged between 20 and 40 years underwent tape measurements of penile dimensions in the stretched state under the same condition. The mean total penile length was 11.58+/-1.45 cm, the mean granular length was 3.04+/-0.33 cm and the mean girth was 8.66+/-1.01 cm. Multivariate regression analysis showed that penile dimensions are significantly correlated with age (P=0.018), height (P<0.001) and index finger length (P<0.001). This analysis provided no evidence for significant effect of waist/hip ratio and weight on penile dimensions. As the penile augmentation is still in its experimental stage and its indications have not yet been clearly established, providing standardized data on penile dimensions seems to be necessary to make convenient decisions in the counseling and/or treatment of people with short penis concerns.