Thirty boys eight to eighteen years of age had a clearly palpable left varicocele. The presenting complaint usually was either an asymptomatic scrotal mass or a scrotal ache after physical exercise. In 77 per cent of the patients the left testis was smaller than its male. All but one of the 17 boys between ages eight and fifteen had a smaller left testis. When the varicocele is symptomatic, presents as a prominent mass, or where growth of the left testicle lags behind that of its mate, surgical correction of the varicocele is recommended.