Objective. To examine the efficacy of self-regulation of food marketing to children by comparing, during children's preferred viewing on television, the differences in food/beverage marketing between two groups of corporations: 17 corporations participating in the Canadian Children's Food and Beverage Advertising Initiative (CAI) and 35 corporations not participating (non-CAI) in this initiative. Methods. The food/beverage marketing activities of CAI and non-CAI corporations during 99.5 hours of children's preferred viewing on television were compared. First, the preferred television viewing of 272 children aged 10–12 years from Ontario and Quebec who completed TV viewing journals for a seven-day period was determined. A total of 32 television stations were simultaneously recorded, and a content analysis of children's preferred viewing was conducted and included coding all food/beverage promotions and their nutritional content. Each food/beverage promotion was classified by corporation type (i.e., CAI or non-CAI). Results. The CAI was responsible for significantly more food/beverage promotions, and used media characters and repetition more frequently in their food/beverage promotions than the non-CAI group. Nutritionally, the CAI food/beverage promotions were higher in fats, sugar, sodium and energy per 100 grams. A significantly greater proportion of the CAI food/beverage promotions were considered ‘less healthy’ compared to the non-CAI promotions. Conclusion. With the exception of the four corporations that did not market to children at all, the commitments that have been made in the CAI are not having a significant impact on the food and beverage marketing environment on television which is viewed by 10–12-year-olds.