In a prospective study we investigated 100 twin pregnancies in order to assess the predictive value of doppler-sonographic measurements regarding the pregnancy outcome. We used the pulsatility index of the uterine arteries, the umbilical artery, the fetal aorta thoracica and the fetal middle cerebral artery. The measurements were obtained at various gestational ages between 24 and 32 weeks. Significant differences between unselected twin pregnancies and normal single pregnancies were not found. Moreover, there is no relation between the severity of an impaired perfusion and an adverse outcome of the pregnancy. The prediction of fetal distress (hypoxia, preterm birth, poor fetal growth, acidosis, and disturbed neonatal adaption) with doppler-score has a sensitivity of 25% and a positive predictive value of 63%. From this rather insufficient result we conclude that doppler screening in unselected twin pregnancies hardly proves to be useful.