OBJECTIVE We determine the success of end-to-side epididymovasostomy in patients presenting with obstructive azoospermia from primary epididymal obstruction and identify prognostic factors that could predict a successful outcome. METHODS Of 256 consecutive patients undergoing end-to-side epididymovasostomy 49 had primary epididymal obstruction unrelated to prior vasectomy. Patients were excluded from study if they had a history of vasectomy, microsurgical reconstruction or ejaculatory duct obstruction. RESULTS Followup was available in 43 of the 49 patients (88%). Patency rates were 87% in the bilateral epididymovasostomy group, 69% in the unilateral group and 81% overall. Pregnancy rates were 43% in the bilateral and 23% in the unilateral group. While higher patency rates were observed for proximal anastomoses, higher pregnancy rates were observed for distal anastomoses. Intraoperative epididymal fluid quality correlated with patency, that is motile sperm in the epididymal aspirate correlated with postoperative patency (p <0.05). There was no correlation between fluid quality and pregnancy rates. Postoperative semen analyses demonstrated higher sperm density and higher motility in the pregnant versus nonpregnant groups. CONCLUSIONS Epididymovasostomy may be performed in patients with obstructive azoospermia unrelated to vasectomy with high patency and good pregnancy rates. Intraoperative epididymal fluid quality can be predictive of patency. There was a trend towards higher pregnancy rates for distal anastomosis. There were no pregnancies when anastomosis was at the caput epididymis on both sides.