Generic medication market has been increased for economic reasons in Korea. Health authorities worldwide recommend the use of generic medications nowadays. However, patients in Korea are not familiar with the generic medications and considerable percent of those do not know the definition of the generic medications. The purpose of this study was to evaluate adults' knowledge and perception on the generic medications at community pharmacies in Korea. This study was a 11-questionnaire survey conducted from August 9, 2010 to August 27, 2010. Of the 204 respondents, 63 (30.9%) responded that they knew what a generic medication was, but only 16 (25.4%) of those answered that generic medications had the same efficacy as brand medications. When pharmacists were the source of generic medication information, more patients reported having knowledge about the definition of generic medications correctly compared with other sources. Patients with negative experience with generic medications within 6 months were more reluctant to generic substitution suggested by a pharmacist than those with positive experience. Based on the results of this study, further studies should be conducted to establish the best way to provide generic medication information for patients.