Retroperitoneal mobilization of the vas deferens in the complex vasovasostomy. Anatomic distances along retroperitoneal, inguinal, and infrainguinal segments of the vas deferens were measured in 14 formalin fixed cadavers and in 15 recently postmortem males. There were no significant differences in segment lengths between the two groups nor between the right and left vasa. Data from the recent postmortem group reveals a mean length of 5.83 +/- .65 cm to be gained from retroperitoneal mobilization of the vas deferens. This information is important to surgical decisions in cases of microsurgical repair of obstructive azoospermia resulting from damage to the inguinal segment of the vas deferens. Data on other vasal segment lengths is beneficial for planning repair in other complex cases of obstructive azoospermia as well. 