The bacterial flora of the cervix and vaginal vault were compared by obtaining duplicate specimens for quantitative bacteriologic studies in 14 patients electively admitted for hysterectomy. There were a total of 137 isolates from the 28 specimens, including 71 aerobes and 66 anaerobes. Aggregate data showed that the flora of the two sample sites were similar by both qualitative and quantitative analysis. However, individual comparison of paired specimens showed considerable differences in that 75 of the 137 isolates were recovered from only the cervix or vaginal vault. Additional studies showed that neither low concentrations of bacteria nor the culture techniques accounted for these differences. It is concluded that most women harbor distinctive bacterial populations in the cervix and vaginal vault.