OBJECTIVE To assess the effect of a community bicycle helmet education and subsidy program and the further effect of a bicycle rodeo on helmet ownership and use among elementary schoolchildren. The unanticipated effect of a child cyclist fatality was also measured. DESIGN Helmet ownership and use were measured in two ways: a questionnaire was sent to all elementary schoolteachers asking about helmet ownership and use by their students; and volunteers counted the children riding their bicycles to school. SETTING Elementary schools in the town of Goderich, population 7400, and the town of Kincardine, population 6227, both on Lake Huron in southwestern Ontario. PARTICIPANTS More than 80% of the 1050 elementary school students in Goderich and, for comparison, more than 90% of the 1439 elementary school students in Kincardine. INTERVENTIONS An extensive education campaign with programs, assemblies, teaching aids, speakers, and a colouring and poster contest, coupled with a discount helmet offer in October 1991. Incentives to helmet use, such as bicycle rodeos, took place in May 1992 and 1993. A child cyclist not wearing a helmet was fatally injured in September 1992. MAIN OUTCOME MEASURES Teachers polled students on helmet use and student volunteers counted children riding bicycles and noted helmet use. RESULTS A total of 250 helmets were purchased, and helmet use was observed to increase among 5- to 14-year-old children from 0.75% to 12.8% during 9 months. Program effect was significantly greater on younger children, and girls used helmets more often than boys did. The cycling fatality in Goderich was associated with a dramatic increase in helmet use (to more than 50%), a significantly higher rate than in Kincardine. A second subsidy and rodeo did not further increase helmet use. CONCLUSIONS A small community with limited resources can mount a bicycle helmet education and incentive program with high exposure and participation rates by children. Despite an initial 17-fold increase in observed helmet use, more than 87% of cyclists still did not wear helmets. The cycling fatality was associated with a significant increase in helmet use.