OBJECTIVE: This study was designed to examine relations between nocturnal awakenings and unintentional injury risk among toddlers. METHODS: A nationally representative sample of 799 children was followed longitudinally from birth through 36 months. Patterns of nocturnal awakening were assessed by parent-report at ages 6, 15, 24 and 36 months, and injury events were reported at quarterly intervals over the same time period. A range of external covariates, including positive and negative affect and externalizing behavior; maternal stress, maternal depression, and parenting style; and family socioeconomic status were measured. RESULTS: A persistent pattern of very mild nocturnal awakening was related to increased risk of injury during the toddler years, and that relation held after controlling for a range of potential covariates. CONCLUSIONS: A pattern of persistent nocturnal awakening appears to be related to unintentional injury risk in toddlers.