Because of reports suggesting that spermagglutinins may be involved in female infertility, we tested serum and genital tract secretions over a three-year period. Initial studies of serums from 42 infertile patients showed a similar frequency of spermagglutinating activity in those with primary infertility (not due to detectable disease) and other forms of infertility. Analysis of serum, uterine, and vaginal secretions from another 31 infertile women showed that spermagglutinating activity was less frequent in the genital tract secretions than in serum. Among the total group of 73 women with various types of infertility, no significant difference in serum spermagglutinating activity was found. Our results do not encourage belief that spermagglutinating activity plays an important role in female infertility. © 1973 American Medical Association. All rights reserved.