The presence of sperm in the intravasal fluid during vasovasostomy is an indication that the procedure will be successful in a large percentage of cases. Intravasal azoospermia (IVA) raises the possibility of an additional obstruction caused by fibrosis of the epididymis, a pressure related effect of vasectomy. The frequency of epididymal fibrosis may be related to the obstruction interval, the time between vasectomy and reversal. 161 microsurgical vasovasostomies were reviewed. In each case the presence or absence of sperm in the intravasal fluid was determined and when present, microscopic morphology and degree of motility were noted. 20 of the 161 patients had bilateral IVA; 10 were available for longterm follow-up. The obstruction interval ranged from 4-12 years, with an average of 7.5 years. 6 cases, with an average obstruction of 7 years, gained a normal sperm count within 1 year of the operation. The 4 cases remaining azoospermic had an average obstruction interval of 8.25 years. Gross appearance of the intravasal fluid was recorded for each of the 10 cases. For patients who gained a normal sperm count, the fluid was watery in 3 vasa, opalescent in 3 vasa, and creamy in 6. In cases remaining azoospermic, intravasal fluid was opalescent in 4 and creamy in 4. The data indicate that for obstruction intervals of less than 12 years, IVA during vasovasostomy is not usually associated with epididymal fibrosis and is reversible in over 1/2 of the cases. Therefore, finding IVA is not necessarily an indication for vasoepididymostomy. The tunica vaginalis should be opened and the epididymis inspected. Obstruction is characterized by the presence of a specific area of fibrosis with homogeneous proximal dilatation of the epididymal tubule which is visualized through the epididymal capsule and filled with creamy or white fluid. If the epididymis is not clearly obstructed, IVA is not an indication for vasoepididymostomy, especially at the shorter intervals. At longer intervals, more than 12 years, a higher degree of suspicion of epididymal sclerosis is appropriate.