The cervical-vaginal flora of 21 women with invasive cervical cancer was determined. The cultures yielded polymicrobial growth with anaerobic organisms predominating. As compared with other studies of vaginal flora, the cancer patients were found to have a decreased frequency of isolation of aerobic lactobacilli, Staphylococcus epidermidis. and enterococci, and an increased frequency of isolation of Escherichia coli and Bacteriodes species. The composition of the anaerobic vaginal flora in these patients is similar to that described for immunosuppressed renal transplant patients.