Objective: Identify the prevalence of sleep disordered breathing (SOB) symptoms in a community sample of New Zealand 3-year olds. To examine sleep, demographic, health, environmental, familial, perinatal, and behavioral adjustment factors associated with habitual snoring. Methods: A cross sectional study, in which parents of 823 children aged 3 years 0 months to 3 years 12 months (M:F = 1:0.9) were recruited from the community. Participants completed questionnaires designed to assess information relevant to their children's sleep, with a particular focus on snoring. Results: Parents reported snoring at least once a week in 36.9% of children, and habitual snoring (more than four nights per week) in 11.3% of children. Univariate analysis showed habitual snoring was more common amongst Maori (indigenous New Zealanders) (P = 0.04) and males (P = 0.05), and that habitual snorers came from more socio-economically deprived neighborhoods (P < 0.01). Several other SDB-related symptoms were significantly associated with habitual snoring: mouth breathing, sweating profusely, waking during the night, sleeping with neck extended, constant runny nose, and suffering from tonsillitis. Mouth breathing was the most strongly associated. Multivariate analyzes revealed a strong positive relationship between snoring and some health and familial factors, as well as parent reported child irritability (OR = 2.83; 95% CI 1.4-5.6) and hyperactivity (OR = 1.6; 95% CI 1.0-2.7). Conclusions: The prevalence of habitual snoring amongst New Zealand pre-schoolers is similar to that reported elsewhere. Factors associated with habitual snoring include male gender. Maori ethnicity, and poorer deprivation neighborhood, as well as a variety of other environmental and health factors. The data provide evidence that habitual snoring associated with irritable and hyperactive behavior is evident in children as young as three. (C) 2012 Elsevier B.V. All rights reserved.