OBJECTIVES: Consumer opinions are important to increase use of less expensive generic drugs. The objective of this study was to examine factors that may affect consumer perceptions regarding generic drug substitution practices. METHODS: Data were collected from consumers filling prescriptions at 10 Walgreen stores situated around Houston (N = 1000) by administering a survey. Factors such as prior drug purchase behavior and role of pharmacists were measured using four items on a 5-point scale where 1 = never and 5 = always. Consumer perception about generic drugs was measured using a semantic differential scale. A 5-point Likert scale was used to evaluate their perception regarding drug substitution practices. Demographic data such as age, gender, education and income were collected and analyzed to perform descriptive and correlation analyses. RESULTS: A total of 505 completed surveys were analyzed. The mean age was 42.63 (3/4 15.8) years with 90.51% being enrolled in the health plan. Majority were female (62.02%) and fulltime employees (61.9%). Respondents had a positive attitude towards generic drugs (3.84 3/4 0.89) and drug substitution practices (3.74 3/4 0.79). The correlation analysis indicated a positive correlation between consumers ¢ perception regarding drug substitution practices and prior use of prescription (r = 0.49, p <0.05) and non-prescription drugs (r = 0.28, p <0.05). Although half of the participants (54%) indicated that they never refused their pharmacists for substituting with a generic drug, only 11.20% of the participants indicated being always asked by their pharmacists for such substitution. CONCLUSIONS: Consumers' positive perceptions towards generic drug and generic drug substitution practices could help drug management strategies by managed care organizations to reduce health care costs. Pharmacists may need to be provided incentives to actively promote generic substitution to consumers.