Objective to evaluate the levels of IL-8 in cervical mucus in relation to presence of vagial bacteria in women in preterm labour (PTL). This study was performed on a prospective follow up study that include 105 women with singleton pregnancies (34 weeks) presenting with risk PTL and quantification the concentration of IL-8. The results showed that Lactobacillus species were detected in 17/55 subjects (30.9 percent) with high IL-8 (360ng/ml), significantly less than the rate of subjects with normal level of IL-8 36/50 (72 percent, p0.0001). Anaerobic pathogens were detected in 78.2 percent of high IL-8 subjects, significantly more than in normal IL-8 subjects (42 percent, p0.0001). The authors concluded that the absence of vaginal Lactobacillus were associated with increased IL-8 in cervical mucus and increased risk of premature delivary.