Objective: Describe beliefs about what makes foods healthful among low-income African American women. Methods: In one-on-one interviews, 28 low-income African American mothers viewed 30 pairs of familiar foods and explained which food in the pair was more healthful and why. Responses were grouped into codes describing concepts of food healthfulness. Results: Nutrient content, physical effects of food, and food categories were used to judge the healthfulness of foods. Fruits, vegetables, and dairy foods were considered the most healthful and starchy foods the least healthful because they were believed to cause weight gain. Beliefs about which foods contain which nutrients and which foods have particular physical effects varied widely across participants. Conclusions and Implications: Participants demonstrated awareness of which foods are healthful but lacked understanding of why those foods are more healthful than others. Knowledge about the health effects of foods may be necessary to motivate individuals to choose healthful foods. (Contains 2 tables.)