Sleep terrors are nocturnal episodes characterized by screams, cries, and confusion lasting a few seconds to a few minutes. This parasomnia is especially prevalent in toddlers and has been associated with separation anxiety. While sleepiness and reduced sleep quality have been reported in adults with sleep terrors, it is unclear whether this holds true in children. The objectives of this study were to investigate whether sleep terrors were associated with sleep latency, duration and fragmentation, and emotional-behavioral problems. Participants were children from the Maternal Adversity Vulnerability and Neurodevelopment longitudinal cohort (N=509). Maternal reports were used to assess the presence or absence of sleep terrors and sleep habits (sleep latency, total nocturnal sleep duration, consecutive hours of sleep) when children were 12, 18, 24, and 36 months old. Internalizing and externalizing problems were assessed at 48 months with the Children Behavioral Checklist (maternal report). Sleep terrors were reported in 21% of 12 months old children, 16% of 18 months old, 20% of 24 months old, and 19% of 36 months old. Results from a generalized estimating equation model showed that, while controlling for total nocturnal sleep duration, the presence of sleep terrors in children was associated with longer sleep latency (p<0.05), and less consecutive hours of nocturnal sleep (p<0.05). Sleep terrors were also associated with increased internalizing and externalizing problems (p<0.05). The frequency of sleep terrors in our sample was similar to what is reported in the literature. Toddlers presenting sleep terrors had a more fragmented sleep, i.e. longer latency and less nocturnal sleep consolidation. It is not yet clear whether sleep terrors lead to increased sleep fragmentation, or whether they are triggered by fragmented sleep. Present results also suggest that sleep terror might represent an early sign of emotional-behavioral problems in toddlers. CIHR, Ludmer Centre for Neuroinformatics and Mental Health