To describe ready-to-eat (RTE) cereal purchases in 2008 in the USA according to cereal nutritional quality and marketing strategy and household sociodemographic characteristics. Cross-sectional study of purchases in one year. Each type of cereal was assigned to one of four nutrition quality categories (based on Nutrient Profile Index, NPI) and one of four advertising categories based on television exposure and analysis of packaging (child-targeted, family-targeted, adult-targeted and no television advertising). Medians and distributions of purchase indicators were calculated for the cereal categories and the distributions were compared across sociodemographic groups. RTE cereals (n 249) with complete label and nutritional content. RTE cereal purchases according to household sociodemographic characteristics obtained from Nielsen Homescan, a nationally representative panel of households. Purchases of RTE cereals were highest in households with one or more child and lowest in African-American and Asian households, as well as those earning <$US 30 000 per annum. The lowest-quality products were purchased by four times as many households as the highest-quality cereals, but loyalty to these products was lower. Purchases of cereals by households with children and in African-American and Hispanic households increased as cereal nutritional quality declined. Compared with non-advertised products, advertised child-targeted cereals were purchased thirteen times more frequently; family-targeted brand purchases were ten times higher; and adult-targeted cereals were purchased four times more frequently. Our findings suggest that improving the nutritional quality of RTE cereals with advertising targeted to children could also lead to increased consumption of healthier products by young people.