OBJECTIVE To demonstrate the long-term patency of microsurgical anastomoses between the internal spermatic vein and the inferior epigastric vein, constructed in the treatment of essential varicocele in paediatric patients to supplement ligation of the spermatic veins. METHODS We submitted 66 patients to inguinopelvic colour-flow Doppler ultrasonography. The patients had been treated 18 - 36 months earlier for essential varicocele by microsurgical inguinal ligation of the testicular venous pedicle and anastomosis between the internal spermatic vein and the inferior epigastric vein. RESULTS Preoperatively, the 66 patients operated on at ages ranging from 10 to 16 years (13 +/- 1.4) presented with Dubin and Amelar grade II (14 patients) or grade III (52 patients) left varicocele with ipsilateral testicular hypotrophy. The postoperative follow-up showed 2 cases of persistence of disease and 3 cases of persistence of "medium" spermatic vein reflux without clinical evidence of varicocele. Seven patients developed left hydrocele which resolved spontaneously in 5 cases, whereas in 2 cases it proved necessary to perform an eversion of the tunica vaginalis of the testis. The results obtained in patients treated for Coolsaet type I varicocele (64 patients) were as follows: long-term patency of the anastomosis was observed in 58/64 patients (90.6 %); in 4 patients (6.2 %) the left inferior epigastric vein presented a position in relation to the homologous artery that prevented adequate sampling and thus made it impossible to assess the patency of the anastomosis; in 2 patients (3.1 %) the anastomosis was closed. In the two patients who had submitted to anastomosis for Coolsaet type III varicocele, colour-flow Doppler failed to identify the shunt. CONCLUSIONS The results of this study demonstrate that microsurgical anastomosis between the internal spermatic vein, and the inferior epigastric vein remains competent in the long term, thus confirming the validity of this technique for the treatment of essential varicocele in children.