This study was conducted to examine the effect of height and weight on the incidence of varicocele in schoolboys aged 5-16 years and the impact of varicocele on testicular size. Genital stage, height, weight, varicocele grade, and testicular size were recorded for 3047 school boys who were clinically examined while standing by a specialist in urology. Left varicocele was detected in 98 of the boys who were all aged 9-16 years. The mean weight of boys with and without varicocele was 42 kg (95% confidence interval [CI] 40-44 kg) and 47 (95% CI 47-47 kg), respectively (p =.00). There was no difference in mean height between the two groups nor in left and right testicular volume. Although 6 boys with varicocele had a left testicular volume > or =2 mL less than right, there were also 7 boys of comparable age who had a left testicular volume > or =2 mL larger than right. The incidence of varicocele in Greek adolescents is low. Boys with varicocele weighed significantly less but there were no significant differences in height or left versus right testicular volumes. In the light of these observations, the use of left testicular hypotrophy (> or =2 mL compared with the right testicle) should be reconsidered as an indicator for varicocele-induced damage of the testicle in this age group.