The aim of this study was to evaluate cerebellar growth of preterm infants. Vermis height and transverse cerebellar diameter were measured by cranial ultrasonography in 38 preterm infants (27-32 weeks) at birth and term equivalent age. Measurements were compared with 40 term appropriate-for-gestational-age infants. Preterms at term equivalent age had larger vermis height than term infants (2.39 +/- 0.25 cm vs 2.25 +/- 0.18 cm, P = .005), whereas no significant difference was found in the transverse cerebellar diameter (5.32 +/- 0.38 cm vs 5.44 +/- 0.23 cm, P = .13). Vermis height and transverse cerebellar diameter of appropriate-for-gestational-age preterm infants (n = 29) were found larger than small-for-gestational-age ones (n = 9). Vermis height and transverse cerebellar diameter at term equivalent age of appropriate-for-gestational-age preterm infants born before and after 29 weeks of age showed no significant difference. Cerebellar growth is preserved in extreme preterms. However, being small for gestational age may have deleterious effects on cerebellar development.