Selenium (Se) is an essential nutritional element for humans. A low Se status has been documented in formula-fed small-for-gestational age (SGA) newborns in the first month of life. The aim of the study was to compare the nutritional selenium status in adequate-for-gestational age (AGA) and in SGA newborns in the first month of life in relation to feeding type. Se status was assessed by plasma and erythrocyte concentrations, determined by pulsed Zeeman effect-atomic absorption spectrophotometry. We studied 210 newborns divided in groups according to birth weight (129 AGA, 81 SGA ) and feeding type (breast milk, formula, mixed) in wk 1-4 of postnatal life. Erythrocyte Se levels are affected neither by feeding type nor by birth weight. Se plasmatic concentrations were lower in SGA than in AGA newborns. Significant differences in mean plasma concentrations were found between formula-fed and breast-fed (p=0.013) and between formula-fed and mixed-fed (p=0.006) SGA newborns. The difference was not significant in AGA neonates. Breast-fed SGA newborns consistently showed higher plasma Se concentrations than formula-fed newborns. Unless supplemented from birth, Se intake will be inadequate in bottle-fed SGA infants.