Aim: To evaluate the effect of gender, gestational age, birthweight, mode of delivery, 5'-Apgar score and maternal conditions on calprotectin concentrations in meconium., Methods: Calprotectin was measured in 131 neonates, in the first passed meconium., Results: Calprotectin levels (mean +/- SD) resulted in 145.2 +/- 78.5 mg kg(-1) meconium, significantly correlated with birthweight (r = -0.333; p < 0.001), gestational age (r = -0.206; p = 0.018) and 5'-Apgar score (r = -0.243, p = 0.035). The estimated regression model was: calprotectin levels (mg kg(-1)) = 269.58-41.54 weight (kg): r = 0.383, p < 0.001. No differences were found in relation to gender, mode of delivery and maternal conditions., Conclusion: Calprotectin is already present in the first passed meconium, with higher levels in preterm and low birthweight neonates, as well as in neonates with some degree of perinatal asphyxia, as indicated by the negative correlation with 5'-Apgar score. These findings are probably secondary to both the immaturity of the intestinal mucosa and its hypoxic-ischaemic damage.