Aims: To evaluate if neonatal complications or death were poorer for neonates born small for gestational age (SGA) than for those born with adequate weight or large for gestation age (LGA) to women with gestational diabetes mellitus (GDM). Methods: Retrospective analysis of the clinical outcomes of neonates born to 3413 women with GDM. The prevalence of neonatal hypoglycaemia, hypocalcaemia, hyperbilirubinemia, polycythaemia, and death was compared among three birthweight groups: SGA, adequate, and LGA. A two-sided chi-squared or Fisher's exact test was used for between-group comparisons. A forward multiple logistic regression was performed to determine the odds ratio (OR) associated with SGA. Results: Neonatal complications were more frequent in the SGA group (20.1%) than in the adequate (9.9%) or LGA (15.2%) groups. There were four deaths (1.6%) in the SGA group compared to one in the LGA (0.4%) and six in the adequate (0.2%) groups (P = 0.002). SGA was a risk factor for neonatal complications or death (OR. 2.122; 95% confidence interval, 1.552-2.899), independent of maternal age, weight gain, fasting glucose, glycaemic control, gestational hypertension, pre-eclampsia, smoking, or neonatal prematurity. Conclusion: SGA birthweight is an important risk factor for neonatal complications or death among neonates born to mothers with GDM. (C) 2019 Elsevier B.V. All rights reserved.