Summary Introduction: The diagnosis of intraamniotic infection (IAI) is usually based on clinical signs and symptoms chich are not always distinct and specific and may be probematic. Thus, a search for more sensitive markers, such as procalcitonin (PCT), and several cytokines in serum of pregnant women to predict IAI development, seems necessary. The goal of the study was to evaluate the usefulness of PCT, IL-6 (interleukin 6) and CRP (C-reactive protein) concentrations in prediction of IAI development and newborn status. Material and methods: In serum of pregnant women (46 women with clinically diagnosed premature rupture of membranes) the concentrations of PCT was measured by immunolumimetric assay, of IL-6 by ELISA kit, and of CRP by turbidimetric methods. To investigate the usefulness of the markers in predicting newborn infections and pregnancy prolongation, we have calculated sensitivity, specificity, negative, positive prognostic value and the area under the ROC curve (AROC – Area under Receive Operating Characteristic). Results: PCT has the highest predictive value in predicting clinical symptoms of IAI in newborns (AROC 0.647, cut point - PCT concentration 0.5mg/dL). The highest predictive value for IL-6 was obtained in predicting the time of pregnancy prolongation since the moment of the test to the delivery (AROC 0.690 for 7 days of pregnancy prolongation, cut point - IL-6 concentration 7pg/ml). During analysis of CRP, the highest predictive value was obtained in predicting the newborn status, evaluated by the Apgar score in the first minute of life (AROC 0.706, cut point - CRP concentration 20mg/dL). Conclusions: Analysis of PCT and IL-6 concentrations in serum allows to identify women that are more likely to deliver newborns with symptoms of severe infection. In cases of severe infection, the usefulness of PCT measurement surpasses any currently used methods, such as CRP concentration measurement, for example. This investigation confirmed the usefulness of IL-6 and CRP measurement in predicting the duration of time from the examination to delivery.