Abstract We examined Iowa Cooperative Extension Service clientele's beliefs about food chemicals in order to identify areas of misinformation, demographic characteristics of clientele who were likely to be misinformed, and common sources of nutrition information. Men and women were randomly selected (n = 1060) from Iowa Cooperative Extension Service mailing lists and asked to respond to a mailed survey of 96 statements representing popular misconceptions about food chemicals. Survey participants ranked the statements on a 99-point scale based on the strength to which they agreed or disagreed with each statement. Using factor analysis techniques, we identified five factors: food contamination by chemicals, naturally occurring vs. synthetic food chemicals, practices that enhance health, need for vitamin supplementation, and hyperactivity. Comparison of mean scores of respondents (n = 420) with mean scores of nutritionists (n = 4) revealed that the greatest difference of beliefs was in the area of hyperactivity, followed by natural vs. synthetic food chemicals, the need for vitamin supplementation, chemical contamination of food, and practices that enhance health. Women had stronger beliefs than men in all categories except practices that enhance health. Education was correlated negatively with all factor categories. Belief in factor statements was correlated most often with use of television, popular nutrition books, friends, and nutrition salespeople as sources of nutrition. Medical doctors, extension bulletins, and mass media were used most often as sources of nutrition information. Our results can be used to design educational materials about chemicals in food.