Objective: The aim of this study was to determine the value of amniotic fluid interleukin-6 (IL-6) and C-reactive protein (CRP) levels in the prediction of preterm delivery in singleton pregnancies without any known risk factors for preterm delivery in Turkish women. Materials and Methods: Patients in the present perinatology department who underwent mid-trimester genetic amniocentesis due to evidence of increased risk of aneuploidy in their prenatal serum screening tests were included in the study. A sample of amniotic fluid from each patient was assessed for IL-6 and CRP. Concentrations of IL-6 and CRP in the amniotic fluid of preterm delivery and term delivery groups were compared. Results: Of 151 singleton pregnancies, 142 participants were included in the study. The participants were assigned to either the preterm or term delivery group based on pregnancy outcome. IL-6 levels in the amniotic fluid were significantly higher in the preterm delivery group, and there was a statistically significant negative correlation between IL-6 concentrations in the amniotic fluid and gestational age at delivery (correlation coefficient (CC): -18.5%, p < 0.05). A negative correlation was also detected between CRP levels in the amniotic fluid and gestational age at delivery, but the correlation was not statistically significant (p = 0.068). Conclusion: Measuring IL-6 in the amniotic fluid can identify women at risk of preterm delivery. Because it is not acceptable to perform amniocentesis for this screening, it is more convenient for patients in whom genetic amniocentesis is performed.