Objective: To identify the characteristics of people consuming olestra-containing foods when first introduced at a test-marketing site. Design: Data are from the Olestra Postmarketing Surveillance Study (OPMSS). After the introduction of olestra into a large test-marketing site, study participants received 3 follow-up telephone calls, at 3-month intervals, in which they were questioned about their diets during the previous month. Subjects/setting: 1,007 adults in Indianapolis, Ind, who participated in a baseline clinic visit (before introduction of olestra into the food market) and completed at least 2 of 3 follow-up telephone calls (after the introduction of olestra into the market). Statistical analyses performed: Logistic regression was used to examine associations between olestra consumption and sociodemographic characteristics, health conditions, attitudes toward health and diet, and health-related behaviors. Results: Olestra consumption on at least 1 of the follow-up telephone calls was reported by 41.5% of the study sample, and consumption on 2 or more telephone calls was reported by 20.0% of the sample. Factors associated with early adoption of olestra-containing foods included white ethnicity, higher education, overweight, absence of diabetes, attitudes indicative of diet and health concerns (eg, perceptions that there is a strong relationship between diet and disease), and a lower fat intake. Applications/conclusions: In spite of the controversy surrounding the introduction of olestra into the food market, persons with attitudes indicative of diet and health concerns were likely to be early adopters of olestra-containing foods. Dietitians and other health care providers should inquire about intake levels of foods with fat substitutes and ensure that these foods are not being consumed in excessive amounts or being consumed instead of nutrient-dense foods that are naturally low in fat.