Our purpose was to evaluate prognostic value of antepartum amniotic fluid index (AFI) on fetal and newborn outcome, because oligohydramnion is associated with increased risk of fetal and newborn distress. Perinatal outcome was defined by 1' and 5' Apgar score, intrapartum fetal heart rate (FHR), blood gas, acid-base status in umbilical artery, mode of delivery and meconium-stained amniotic fluid. Data was analysed with CSS Statistica for Windows package by test t for independent samples and chi 2. Prospective observations was conducted with 84 singleton pregnancies complicated by oligohydramnion (AFI < or = 5 cm). A 336 pregnant women, with normal amniotic fluid index and no complicated pregnancy, was considered as controls. No increased operative delivery and meconium-stained amniotic fluid rate was noted. There was no significant effects AFI on blood gases in umbilical artery and Apgar score. Oligohydramnion was associated with increased risk of fetal acidosis (pH < 7.16) (p = 0.009) and abnormalities of FHR (variable decelerations) (p = 0.004). Reduced AFI had poor predictive value of fetal acidosis and newborn depression positive predictive value (8-13%). Summarizing the results, our investigation showed that amniotic fluid index is only one point in the prognosis of perinatal outcome.