Purpose: The purpose of this study was to explore the moderating effects of heavy versus light shoppers on antecedents of customer’s satisfaction and loyalty toward an Internet retailer. Design/Methodology/Approach: A model discusses the different mechanisms in building an effective exchange relationship with light versus heavy shoppers was developed and tested using Internet book store as the study object. With the assistance of a marketing research firm, an Internet-based survey was employed to gather information on 375 users of Internet bookstores in Taiwan. Findings: The results showed that price/value had a stronger effect on overall satisfaction for light versus heavy shoppers, while trust had a stronger effect on overall satisfaction for heavy versus light shoppers. The study also found that consumers’ irreplaceable asset generated from past transaction with a focal Internet retailer had strong effects on their loyalty responses. Implications: Understanding of the moderating role of heavy versus light shoppers on satisfaction and loyalty formation helps to advance our theoretical understanding of the different routes of satisfaction and loyalty formation for different shoppers. The results of this study can help to inform the practitioners that price may play a role in drawing light shoppers, while perceived trust of the Internet store is more important in retaining heavy shoppers. It also demonstrated the importance of building asset specificity in increasing customer loyalty. Originality/Value: This is one of the first studies to provide evidence of the moderating e fects of heavy versus light shoppers on satisfaction and loyalty formation. It explained and tested empirically the different mechanisms of satisfaction and loyalty formation between two groups of consumers.