The results of microsurgical epididymovasostomy for congenital and acquired vasoepididymal obstruction were retrospectively reviewed in 22 patients in an attempt to determine what preoperative or intraoperative factors might predict surgical success. The overall success rate, defined as sperm on postoperative semen analysis, was 48%. The presence of sperm on an intraoperative touch preparation from the epididymis was significantly correlated with response (chi-square 3.24, p < 0.10) and no patient without sperm on touch preparation had sperm on subsequent semen analyses. Testicular biopsy positive for spermatogenesis and presence of motile sperm on intraoperative touch preparation were not statistically significant predictors of response. These results suggest that presence or absence of sperm on intraoperative touch preparation is the only significant prognosticator of successful microsurgical epididymovasostomy.