The prevalence and familial patterns of night eating syndrome (NES) in families enrolled in the Québec Adipose and Lifestyle InvesTigation in Youth (QUALITY) study was examined. Families (n = 395; one child, mother, and father for whom at least one parent was obese or had abdominal obesity) completed the Night Eating Questionnaire (NEQ) as part of a longitudinal study on the development of metabolic disease in children at risk for obesity. Responses on the NEQ were used to establish a diagnosis of NES and to determine the correlation and heritability of NES symptoms in families. Using comprehensive research diagnostic criteria, full threshold NES was rare: 0% of children, 0.5% of mothers, and 0.3% of fathers met criteria. When controlling for age, sex, and BMI, NEQ scores of spouses were not significantly correlated, but mothers' NEQ scores were significantly correlated with the scores of both sons (r = 0.19, P < 0.001) and daughters (r = 0.15, P = 0.05). The heritability of NEQ scores was 0.24 when controlling for age, sex, and BMI. These findings replicate previous research suggesting a low prevalence of night eating behavior in children and the aggregation of NES in families.