Cervical secretions from 14 women seropositive for HTLV-III/LAV were obtained between days 7 and 21 of the menstrual cycle and cultured for virus. HTLV-III/LAV was isolated from cervical secretions in 4 of 14 women, as well as from blood of 7 of 13 women tested. Female genital secretions may therefore be a source for sexual transmission of the virus to men.