The authors report their experience with the color Doppler ultrasound in the diagnosis and follow-up of patients with varicocele. The features and advantages afforded by this technique are described and attention is focussed to the contribution of technological advancement to the urological armamentarium. We report on 18 cases of varicocele, 2 of which were grade I (preclinical), that had been diagnosed by this technique and confirmed at surgery. In this series the scrotal scintiscan proved to be less specific and was falsely negative in one of the two grade I varicoceles.