A 2005 review by the Institute of Medicine of the National Academies concluded that food marketing influences children's food preferences, consumption, and health. Given the powerful influence of marketing on children's diets, this cross-sectional study examined the types of foods, the nutritional quality of those foods, and the marketing techniques and messages used in food advertising during Saturday morning children's television programming. During 27.5 hours of programming in May 2005, 49% of advertisements shown were for food (281 food advertisements out of 572 total advertisements). The most commonly advertised food categories were ready-to-eat breakfast cereal and cereal bars (27% of all food advertisements), restaurants (19% of food advertisements), and snack foods (18% of food advertisements). Ninety-one percent of food advertisements were for foods or beverages high in fat, sodium, or added sugars or were low in nutrients. Cartoon characters were used in 74% of food advertisements, and toy or other giveaways were used in 26% of food advertisements. About half of food advertisements contained health/nutrition or physical activity messages and 86% of food advertisements contained emotional appeals. This study provides food and nutrition professionals with information about the amount and types of food children are encouraged to eat during Saturday morning television programming. The findings can help food and nutrition professionals counsel children about healthful eating and/or develop programs or policies to balance those advertisements with healthful eating messages.