Objective: To evaluate the diagnostic value of cervicovaginal prolactin levels for predicting preterm delivery in women with preterm labor. Materials and methods: The preterm labor group and normal pregnancy group consisted of 75 and 150 patients between 24 weeks and 36 weeks of gestation. The preterm group was further subdivided into two groups. Study group Ia: patients who came up with preterm labor and given tocolytic but had preterm delivery (n = 50). Study group Ib: patients who came up with preterm labor and given tocolytic and delivered full term (n = 25). A single cervicovaginal measurement was made in all the groups. Results: Cervicovaginal prolactin was highest in the study group Ia (11 ± 9.31 ng/mL) as compared to the study group Ib (4.61± 6.2 ng/mL) and control group (2.51 ± 5.1 ng/mL), and the difference was statistically significant (p = 0.0311; p = 0.0000). The optimal cut-off value of prolactin was greater than 7 ng/mL in study group Ia with sensitivity level of 78%, at a specificity of 80% with positive and negative predictive values of 88.64% and 64.52%, respectively. The area under the receiver operating characteristic (ROC) curve was 79% which indicates fair diagnostic accuracy of cervicovaginal prolactin in predicting preterm labor. Conclusion: Prolactin is a potential biochemical marker which can be used alone or complementary to other markers for predicting preterm labor.