Disproportionate macrosomia refers to excessive weight characterized by a high weight/length ratio. Disproportionate macrosomia is associated with an increased likelihood of neonatal complications. The aim of the study was to investigate incidence of ponderal indexes and disproportionate fetal growth rate in newborns originating from IDDM and healthy pregnancies. 144 IDDM pregnancies and 432 uneventful pregnancies with normal findings of oral glucose tolerance test were studied, and matched 1:3 for gestational age, sex of newborn, mothers's parity and year of delivery. The pregnancies selected terminated between 30-40th gestational week and resulted with live birth. Mean birth weight (+/- SD) in IDDM group was 3558 +/- 817.6 compared to 3132.4 +/- 534.4 grams of control group (F = 51.49; p < 0.001), mean birth length was 49.8 +/- 3.5 vrs 49.1 +/- 2.5 (F = 8.55; p < 0.005), mean gestation age by examination for both study groups 37.9 +/- 1.9, mean ponderal index of IDDM group was 2.82 +/- 0.28 vrs. 2.63 +/- 0.24 (F = 64.52; p < 0.001) of control group, rate of Apgar score < 7 was 21.14% vrs. 5.08% (chi 2 = 30.30; p < 0.001). 53.4% of IDDMs had macrosomia compared with 8.33% of control infants (chi 2 = 140.25; p < 0.001), and 35.24% of IDDMs had disproportionate macrosomia compared with 5.79% of control infants. Significantly higher rate of both proportionally and disproportionally grown infants with macrosomia was found among IDDMs than among control infants. The rate of disproportionate macrosomic infants significantly differ among study group.