Introduction: This study examined the use of helmets in adults, adolescents, and children in a western Canadian province that has no helmet legislation. Methods:A prospective survey of cyclists in two urban Alberta regions was completed. Cyclist demographics, helmet wearing and helmet use were recorded.Results: Helmets were observed in 2,259 (55%; 99% CI: 52-57) of 4,141 cyclists; however, only 75% (CI 71, 78) were wearing the helmet properly. Patterns of use varied according to age: 75% (CI 71, 78) of children, 29% (CI 23, 34) of adolescents, and 52% (CI 49, 55) of adults wore helmets. Percentages were higher in Calgary than Edmonton (63% vs. 45%; p<0.0001) and females wore helmets more often (64% vs. 50%; p<0.0001).Discussion: These results identify large within-and between-region variation in the use of cycling helmets in Alberta. Injury prevention planners need to use these data to adopt interventions that are focused on age groupings, gender, and place of residence.La traduction du résumé se trouve à la fin de l'article.