We examined 11 patients with acquired obstructive azoospermia resulting from irreparable obstruction of 1 vas deferens and severe damage to the contralateral testis. All of the patients underwent transseptal crossed vasovasostomy with no morbidity. Of 8 patients evaluated with postoperative semen analyses 4 (50 per cent) demonstrated total sperm counts of 29 to 205 million and 2 pregnancies (25 per cent) have been reported, with followup ranging from 5 months to 2 years. The etiologies of the vasal obstruction included previous inguinal surgery in 7 patients, vasectomy in 1, ejaculatory duct obstruction in 1, ectopic ureter in 1 and vasal agenesis in 1. Factors leading to loss of the contralateral testis were torsion in 5 patients, mumps orchitis in 2, varicocele in 1, pediatric inguinal herniorrhaphy in 1, epididymal blow out in 1 and unknown in 1. A representative case involving a unilateral ectopic ureter emptying into the seminal vesicle and subsequent contralateral testicular torsion is presented. The results indicate that a transseptal crossed vasovasostomy should be done in patients satisfying the criteria presented.