AIM:To determine characteristics of death in children with neonatal abstinence syndrome (NAS). METHODS:A population-based linkage study of children from birth to 13 years of age in New South Wales (NSW), Australia, born 1 July 2000 to 31 December 2011. Infants with an International Statistical Classification of Diseases and Related Problems, Australian modification coding of NAS (P96.1, n = 3842) were compared to infants (n = 1 018 421) without NAS by birth, hospitalisation and death records linkage. RESULTS:Forty-five (1.2%) children with NAS died, compared to 3665 (0.4%) other children. Most deaths (n = 30, 66%) in NAS children occurred between 1 month and 1 year. Risk of death was independently increased in full-term children (hazard ratio 2.34, 95% confidence interval 1.63-3.35; P < 0.001) from lower socio-economic groups (1.23, 1.12-1.35; P < 0.001), most commonly from ill-defined or external causes, including assault and accidents (P < 0.001). CONCLUSIONS:Children with NAS, especially those of term gestation and from lower socio-economic groups, are more likely to die, especially from external causes.