Normal values for mean platelet volume (MPV) and platelet distribution width (PDW) have not been firmly established for term and preterm neonates. Cord blood samples from 143 healthy newborns (78 full term and 65 premature) were analyzed with the Coulter counter. Platelet count and MPV were significantly greater (p less than 0.05 and p less than 0.001, respectively) in term versus preterm infants, while PDW was significantly less in term infants (p less than 0.001). Platelet count and MPV correlated with gestational age, and platelet count also correlated with birth weight. There was a significant (p less than 0.001) negative correlation of PDW with gestational age and birth weight. These data represent normal reference ranges for neonates and demonstrate significant variation with gestational age.