Supply chain management is an increasingly important organizational concern, and proper management of supplier relationships constitutes one essential element of supply chain success. However, there is little empirical research that has tested the effect of supplier development on performance. The main objective is to analyze the effect of supplier development practices with different levels of implementation complexity on the firm's purchasing performance. Three supplier development constructs were defined: basic supplier development, moderate supplier development, and advanced supplier development. Three structural models were hypothesized and tested using structural equation modeling through field research on a sample of 306 manufacturing companies in Spain. This study identified important interrelationships among the various supplier development practices, basic, moderate, and advanced. Also indicated that the implementation of supplier development practices significantly contributes to the prediction of purchasing performance.