Infants born from multiple pregnancies were observed for three years, 1969-71. Twin births were 1.88% {full-term 1.23%, premature 0,66%) and perinatal twin mortality was 7.94%. The Apgar scale assessment, acid-base balance, physical and psychomotor development equilibration rate, and morbidity, were determined. Great differences were found beween first and second twins, sometimes differing 1000 g in weight. In postnatal disorders the equilibration period was shorter than in single-born children. Examinations after three years did not show much deviation from the norm, although twin pregnancies and deliveries are dangerous and the children are included in the “high-risk” group.