The nature of the local histopathologic changes secondary to vasectomy is described in tissue excised at vasovasostomy in 37 secondarily infertile patients. Segments of surgically removed vasa were also studied in four patients with primary infertility who underwent scrotal explorations and subsequent vasoepididymostomy. Except for infertility, all patients were asymptomatic. Three, often concurrent, inflammatory or proliferative changes were found in 50 of 76 segments of vasa deferentia. These included suture granuloma, sperm granuloma, and vasitis nodosa, the last being a ductular proliferation originating from the central vas lumen and extending into the perivasal soft tissues. Vasitis nodosa occurred in 66% of the patients, and although it was often found with a sperm granuloma, it did occur by itself and is a lesion which should be recognized.