Peroxynitrite generation and subsequent nitration and/or oxidation of proteins, lipids and DNA are implicated in neuronal death. In animal models, peroxynitrite generation is increased by hypoglycemia, a condition occurring frequently in low birth weight newborns. In order to detect systemic nitro-oxidative stress, we developed an assay to measure plasma nitroalbumin (PNA) concentration and investigated its variations according to the occurrence and recurrence of hypoglycemic events (HG: glycemia < 2.5 mmol/l) during the first day of life. PNA concentrations were measured at days 0, 1 and/or 4 of life in 120 low birth weight newborns (27 small for gestational age term and 93 preterm infants). PNA concentrations at days 0, 1 and 4 were significantly higher in infants who developed at least one HG than in normoglycemic patients. PNA concentration at D1 increased with the number of hypoglycemic events and was correlated to the area under curve of glycemia measured 12-24 hours before sampling. We conclude that hypoglycemia during the first 24 hours of life is associated with increased albumin nitration in newborns. Our results suggest that significant nitro-oxidative stress occurs promptly after hypoglycemia implying a risk of end-organ damage due to protein nitration, lipid peroxidation and DNA damage. Evidence of nitro-oxidative stress in hypoglycemic neonates may open new and exciting perspectives in neuroprotection.