A random digit dialing telephone survey was conducted to examine bicycle helmet ownership, use and related factors among 707 children in Metropolitan Toronto. The ownership rate was 22% and use rate 12%. Although ownership was similarly distributed by age and sex, helmet use varied considerably across age strata among boys; only about one fifth of teenaged boys who owned a helmet wore it regularly. Both parental education and annual family income were significantly associated with ownership and use. Past bicycle injuries, although increasing helmet ownership, had no positive impact on use. The strength of a parental role model was reflected in the fact that when parents owned and used a helmet, 93% of their children had a helmet and more than 80% of them always wore it. Since about half of parents are cyclists themselves, helmet promotion activities are likely to maximize their effect if they target both parents and children.