Genital tracts of male Lewis rats were transected at various levels to determine whether this may influence antisperm antibody response. Adult male rats underwent bilateral transection of the vas deferens (group I, n = 9), mid-epididymis (group II, n = 10), and efferent duct (group III, n = 9). Group IV (n = 10) underwent a sham operation. Sera were collected by retro-orbital puncture before the operative procedure and monthly for 3 months postprocedure. Sperm-reactive immunoglobulins IgG, IgA, and IgM were measured individually as well as combined in serum by enzyme-linked immunosorbent assay (ELISA) using lithium diiodosalicylate (LIS)-solubilized washed rat caudal epididymal sperm. The maximal immune response was seen in all groups at 2 months postprocedure. Antibody response defined as the net ELISA absorbance reading for the combined immunoglobulin group were (mean +/- SEM): group I = 120 +/- 16, group II = 156 +/- 23, group III = 190 +/- 20, and group IV = 116 +/- 22. The highest antibody response was noted in the efferent duct group, which was statistically (p < .05) greater than the sham-operated and vas deferens groups. In the efferent duct group the highest immunoglobulin response was observed in the IgG class, which was significantly higher (p < .05) than the IgA and IgM classes. The transection of the male genital tract at different levels leads to variation in antisperm antibody response and that sperm located at different sites along the genital tract may differ in their autoantigenic potential.