Neuroblastoma is a malignancy commonly diagnosed during infancy or early childhood, raising speculation about the role of perinatal factors and risk of disease. Using a case-control design, cases included 155 infants and children aged 0-5 years with histologically confirmed neuroblastoma diagnosed and reported to the New York State Cancer Registry between 1976 and 1987. Controls were randomly selected from the State's Livebirth Registry and were frequency matched to cases on year of birth (n = 310). Medical records of cases were used to verify histology and stage of disease. Data on perinatal factors were ascertained from birth certificates and standardised telephone interviews with mothers. Unconditional logistic regression was used to estimate (un)adjusted odds ratios (OR) and 95% confidence intervals (CI). Both preterm (< 37 weeks) and post-term (> 42 weeks) birth were associated with a reduction in risk (OR = 0.4 [CI = 0.1, 0.9] and OR = 0.3 [CI = 0.1, 0.7] respectively) after controlling for confounders in unconditional logistic regression analysis. Elevated risk factors included: smoking during pregnancy (OR = 1.6; CI = 0.9, 2.8), contracted pelvis (OR = 2.3; CI = 0.6, 9.8), birth injury (OR = 2.9; CI = 0.3, 24.9) and 1-min Apgar Score < or =3 (OR = 6.0; CI = 0.9, 38.6); all confidence intervals included one. These data suggest that extremes in gestation may be associated with a reduced risk, although aetiological mechanisms remain unknown.