Abstract Objective: To investigate whether maternal serum and amniotic fluid CRP and PAPP-A concentrations at the time of genetic amniocentesis are markers of preterm delivery. Study design: One hundred and forty-one pregnant women were included in this prospective study. Amniotic fluid and maternal serum CRP and PAPP-A concentrations were determined by using commercially available kits. Receiver-operating characteristic (ROC) analysis was performed to determine the efficacy of maternal serum and amniotic fluid CRP and PAPP-A levels in predicting women with preterm delivery. Results: The prevalence of spontaneous preterm delivery before 37 weeks of gestation was 9.9%. ROC analysis revealed that amniotic fluid CRP level was the only parameter, which had a significant power in the prediction of preterm delivery. The optimum cut-off level was 0.65 mg/L. The sensitivity and specificity were 92.9% and 78.7%, respectively. Conclusion: The amniotic fluid CRP level has a high sensitivity and specificity in the prediction of preterm delivery and this may be helpful in predicting preterm delivery during genetic amniocentesis.