EDTA enhances the spermicidal activity of nonoxynol-9 (N9) in the presence of cervical mucus. Moreover, the combination of EDTA and N9 in cervical mucus appears to offer protection against sexually transmitted diseases including AIDS. To understand the fundamental basis of altered mucus receptivity to sperm, it is necessary to define the physical and biochemical changes associated with EDTA and N9 application to mucus. It is suggested the chelating action of EDTA alters the glycoprotein composition of cervical mucus. Correlations already exit between the levels of various mucin and protein components of mucus and viscoelasticity and sperm motility. It is suggested that EDTA may also affect such compositional changes physical properties and may also alter protein phosphorylation. In this proposal, the actions of EDTA on such parameters in cervical mucus will be examined.