OBJECTIVE Subject of the study was the significance of umbilical artery Doppler velocimetry findings for the further course of pregnancy and fetal outcome in cases of twin pregnancies. METHODS In 206 cases of twin pregnancy, the umbilical artery was examined using Doppler velocimetry in the median 9 days prior to delivery, and the result was correlated with the further course of pregnancy and fetal outcome. 174 pregnancies showed normal Doppler findings of the umbilical artery (group A), 32 twin pregnancies showed pathological Doppler findings of at least one twin (group B). The median of the maternal age and the parity between the groups were not different. RESULTS In group B (pathological Doppler findings), intrauterine growth retardation and pre-eclampsia occurred 5 times more often than in group A (normal Doppler findings). The total rate of cesarean sections was not different between the study populations; the rate of deliveries by cesarean section in group B was significantly increased by a factor of 2.4 due to a pathological CTG. The median birth weight and the gestational age at birth were significantly lower in group B (1,660 g; 35 weeks) as compared to group A (2,460 g; 37 weeks; p<0.001). In group B, the rate of premature deliveries up to reaching the 34th week of gestation was 3. 4 times higher; the rate of SGA newborns was 6.3 times higher. Perinatal mortality was increased by a factor of 1.5 in group B compared to group A. CONCLUSIONS The Doppler velocimetry findings have considerable effects on the further course of a multiple pregnancy. In case of pathological Doppler findings, early hospitalization and close monitoring of the pregnancy should be performed. In cases of additional pathological findings (maternal illness, pathological Doppler findings of fetal blood vessels), termination of the pregnancy has to be considered.