This research is aimed to analyze consumer behavior in purchasing beef at modern market, located in District of South Bolaang Mongondow, Province of North Sulawesi, viewed from level of interest and performance of various attributes closely attached to beef products. The research, methodologically, then, was performed under survey method to beef's consumers in two supermarkets existing in District of South Bolaang Mongondow. Both supermarkets selected as research site were Media Trans and Hail Mart, having been newly operated since 2018. 100 respondents were selected with accidental sampling technique, 50 respondents of each supermarket respectively. Data obtained were primary data, comprising of consumers' perception against 25 items of beef attributes in-depth questioned under guidance of list of questions prepared initially. To analyze the level of interest and performance of beef attributes sold according to consumers' perception, importance-performance matrix (IPM), thus, was employed. A value given for the level of interest and performance had 5 indicators, ranging of 1-5. As a result, the research concludes that attribute of expired dated, contents of beef's parts and information of halal (under religious practice) were significantly important; however, the performance had not been in accordance with consumers' expectation in influencing purchasing decision. Therefore, as further recommendation, those beef attributes are necessarily required higher priority by management of both supermarkets and beef's producers in improving beef's quality in order to satisfy consumers' demand in purchasing beef products.