Antibody response to poliovirus type I in serum, the nasopharynx, and the secretions of the genital tract was studied in human volunteers after intravaginal, intrauterine, nasopharyngeal, or intramuscular immunization with inactivated poliovaccine. The techniques of radioimmunodiffusion and autoradiography with P32 labeled poliovirus as the antigen were employed to determine antibody activity in the major classes of immunoglobulin in serum and secretions. Intravaginal and intrauterine immunization consistently resulted in the appearance of secretory antibody to poliovirus in the genital tract. The vaginal response was predominantly of γA immunoglobulin, while the response in the uterus was essentially limited to γG immunoglobulin. Intramuscular immunization resulted in a delayed appearance of γG response in the genital tract, which could be correlated with the highest γG antibody titers in the serum. No genital γA response was observed, however, after such immunization. These observations provide evidence for local synthesis of poliovirus antibody in the genital tract, and its implication may be applicable to other genital infections.