Though bicycle head trauma is a significant cause of mortality and morbidity, much of which can be mitigated by wearing protective helmets, in 1986, few schoolchildren in the area of Seattle, Wash, were observed to wear helmets. We describe the mechanics of a multifaceted campaign undertaken to alter this situation, involving a coalition of health, bicycle, and helmet industry organizations. These were the major objectives: (1) to convince parents that riding bicycles without helmets is hazardous, (2) to lower the price of helmets to more affordable levels, and (3) to overcome the reluctance of children to wear helmets. The campaign was successful; the sales of one brand of a youth helmet in the Seattle area rose from 1500 to 22,000 over a 3-year period, and the observed helmet usage rate among school-age children increased from 5% to 16% compared with a rise of only 1% to 3% in a control community, Portland, Ore.