Sperm antibodies were evaluated in serum and semen of 14 cases with bilateral congenital absence of the vas deferens, by agglutination and complement dependent tests. The level of the various immunoglobulin fractions were determined by the single radial immuno diffusion method. Sperm agglutinins were present in serum in 71% of cases and in 29% in semen. Immunoglobin (Ig) M was not detected in semen of both patient and control groups, while IgG and IgA were absent in the semen of patients.