Purchasing integration remains an undr-researched concept, despite described as a key competence in the literature. This study explicates the concept of purchasing integration and examines its relationship with purchasing practices and manufacturing performance. Purchasing integration refers to the integration of the strategic purchasing practices and goals with a firm's objectives. Alternative models linking purchasing integration to purchasing practices and manufacturing performance are hypothesized and tested using empirical data. Purchasing integration was found to moderate the relationship between purchasing practices and manufacturing performance. Increased investments in purchasing integration were observed to lead to higher performance returns from investments in purchasing practices.