The pro-inflammatory cytokine IL-6 may be neurocytopathogenic, and elevated levels are associated with impaired neurological outcome among children born pre maturely. However, the precise mechanisms underlying this association remain unc lear. The rare C (rather than G) variant at position -572 in the IL-6 gene is associated with an increased IL-6 synthetic response. If IL-6 mediates cerebra l injury, we would anticipate the -572 C allele to be associated with impaired childhood development. We have examined this hypothesis, studying 113 Caucasian children born at ≤32 wk gestation. Cognitive and motor functions were assessed using the Griffiths Developmental Scales at 2 y and British Ability Scales (2nd Ed.) and the ABC Movement Score at 51/2 y. Performance (median, interquartile ra nge) in all three scales was worse in the 10 carriers of the C allele than for t hose with GG genotype: Griffiths Developmental Quotient: C allele, 92.4 (89.9-9 6.6) versus CG 100.9 (96.7-104.8), p = 0.002; General Cognitive Ability: C alle le, 88.0 (80.3-102.8) versus GG 103.0 (92.0-112.0), p = 0.037; Movement ABC sc ore: C allele 8.3 (6.6-20.3) versus GG 4.0 (1.0-9.5), p = 0.081. The presence of the rare (≥1) IL-6 -572 Callele (CC+GC genotypes) is associated with impa ired cognitive development among children born before 32 wk gestation. These dat a support a role for IL-6 in the genesis of neurologic impairment in such child ren. The pro-inflammatory cytokine IL-6 may be neurocytopathogenic, and elevated levels are associated with impaired neurological outcome among children born pre maturely. However, the exact mechanisms underlying this association remain unc learned. The rare C (rather than G) variant at position If IL-6 mediates cerebra l injury, we would anticipate the -572 C allele to be associated with impaired childhood development. We have examined this hypothesis, studying 113 Caucasian children born at ≤32 wk gestation. Cognitive and motor functions were assessed using the Griffiths Developmental Scales at 2 y and British Ability Scales (2nd Ed.) and the ABC Movement Score at 51/2 y. Performance (median, interquartile ra nge) in all three scales was worse in the 10 carriers of the C allele than for t hose with GG genotype: Griffiths Developmental Quotient: C allele, 92.4 (89.9-9 6.6) versus CG 100.9 (96.7-104.8), p = 0.00 2; General Cognitive Ability: C alle le, 88.0 (80.3-102.8) versus GG 103.0 (92.0-112.0), p = 0.037; Movement ABC sc ore: C allele 8.3 (6.6-20.3) versus GG 4.0 (1.0-9.5) , p = 0.081. The presence of the rare (≥1) IL-6-572 Callele (CC + GC genotypes) is associated with impa ired cognitive development among children born before 32 wk gestation. These dat a support for role IL- 6 in the genesis of neurologic impairment in such child ren.