Few studies have investigated the relationship between post-natal inflammatory biomarkers at early age and child neurodevelopment outcomes. The main aim of this study was to examine the relationship between IL-6, IL-1 beta, IL-4 cytokines, as well as cortisol at 6 and 12 months of age, and neurodevelopment and psychological problems at 30 months of age. The study was conducted on a sample of 51 full-term newborns who were followed up at 6, 12, and 30 months of age. Infant neurodevelopment was assessed using the Bayley Scales of Infant Development-II, psychological problems were assessed with the Child Behavior Checklist 1.5-5 (CBCL 1.5-5) and the mother's emotional symptoms were assessed with the General Health Questionnaire-28. When the infants were 6 and 12 months old, IL-6, IL-1 beta, IL-4 cytokines, and cortisol were measured in blood samples. The results showed that higher IL-6 at 12 months predicted higher scores in internalizing (emotionally reactive, anxious/depressed, withdrawn and attention problems) and externalizing problems (aggressive behavior) at 30 months. By contrast, high levels of IL-1 beta at 6 months were related to worse motor skills. Inflammatory biomarkers were not related to mental performance. IL-6 and 1-1 beta could be early markers of later psychological problems and psychomotor disabilities. (C) 2017 Elsevier B.V. All rights reserved.