Objective: During pregnancy the placenta and the fetal membranes are the main sources of activin A. An increased level of activin A has been found in the serum of women with preeclampsia, diabetes mellitus and intrauterine growth restriction. Meconium is the predictor for adverse perinatal outcome, such as meconium aspiration syndrome or brain damage. The aim of our study was to evaluate the levels of fetal activin A in labors complicated by meconium-stained amniotic fluid. Material and methods: Cord blood samples were collected from 65 full-term neonates from single pregnancies. In each case, the hematological parameters of cord blood and activin A (ELISA – Oxford Bio-Innovation Activin A Assay Kit) were assessed. Results: There were no significant differences in the concentration of activin A in cord blood between the group with and the group without meconium-stained amniotic fluid. The mean count of nucleated erythrocytes and white blood cells as well as the percentage of reticulocytes was significantly higher in the meconium group. There were no significant differences between concentration of fetal activin A in a vaginal delivery (0,58±0,38ng/ml) and cesarean section after labor (0,44 ±0,32ng/ml) or elective cesarean section (0,62±0,47ng/ml) groups. There were also no correlations between the levels of activin A and the parameters of fetal acid base status or cord blood hematological values. Conclusions: Fetal activin A has a limited significance for diagnosing fetal hypoxia in labors complicated by meconium-stained amniotic fluid. There were no correlations between the parameters of fetal acid base status and fetal activin A. The levels of fetal activin A do not depend on the mode of the delivery. Meconium-stained amniotic fluid resulted in significant changes of the hematological variables in cord blood.