Many firms today are developing collaborative relationships with their suppliers, with some firms even single sourcing products from suppliers. As these long-term relationships develop, criteria used to select suppliers may be subject to change. This study examines the supplier selection criteria of purchasing managers who have a preference for single sourcing and those who have a preference for multiple sourcing. The purpose of this study is to determine if there are substantial differences in supplier selection criteria between purchasing managers having dissimilar preferences for product sourcing decisions. By identifying supplier selection criteria that are different for purchasing managers with disparate preferences, companies can segment their markets in terms of these buying preferences. Differences are found between the two on the importance of price, reliability of the product, technical support available, and total cost of the product in supplier selection.