Objective: The objective of this abstract is to review the characteristics of a multi-institutional series of inguinal vasal obstruction related to Marlex mesh herniorrhaphy (IVO-MM). Design: This study is a case series review, using the “androlog” internet site to gather information and to share case experiences. It is a multi-institutional study. Materials/Methods: Five patients from five institutions in the U.S. reported individual cases of IVO-MM. The patient characteristics, surgical data, etc., were forwarded to one center for tabulation of the data. Results: In total, bilateral obstruction occurred in 3 patients, and unilateral obstruction, with prior unrelated contralateral testis atrophy, occurred in 2 patients. The average patient age was 38.5 years. Average number of years since mesh herniorraphy to time of diagnosis was 3.3 years. The diagnosis was confirmed surgically in three, by seminal vesciculogram in one, and by presumptive history in one. All patients were azospermic at diagnosis. Surgical exploration revealed a dense fibrotic reaction in all cases and only a third could be reconstructed. Conclusions: Surgical injury to the vas secondary to scrotal and inguinal surgery has been reported in the literature, treatable by microsurgical reconstruction. Recently, internet “androlog” case presentations identified several cases of inguinal vasal obstruction related to Marlex mesh herniorrhaphy. We examined the details of these individual cases. The incidence of use of Marlex mesh in inguinal herniorrhaphy is increasing. The incidence/prevalence of IVO-MM is not known. This is the first report of a series of cases of IVO-MM from a multi-institutional study. It appears as though IVO-MM is difficult to reconstruct due to the dense fibrotic reaction in the area of the mesh as described previously in animals. (J Urol 161:1344, 1999). General surgeons should be made aware of these data and should proceed with caution regarding the use of Marlex mesh in patients of reproductive age with bilateral inguinal hernias.