The last decade has seen a rapid increase in the organizational adoption of supply chain management (SCM) concepts in business. A key reason for this has been that webtechnologies and their enhanced capabilities have made integrated supply chain management viable as a managerial and strategic option. Building on prior MIS literature on technology diffusion and SCM research, this study seeks to understand the nuances in using webtechnologies for SCM function in organizations. Based on a large-scale, questionnaire survey of North American organizations, it specifically investigates organizational and environmental factors that influence the internal and external diffusion of web-technologies in the supply chain management function. The paper also investigates the performance impacts of web-technology diffusion, in relation to customer service, cost reduction, inventory management, cycle time reduction, supplier relationship management and competitive advantage. Results suggest that both internal and external diffusion of webtechnologies for SCM has a significant impact on benefits realized. Supplier interdependence and IT intensity were found to be the significant environmental factors impacting the diffusion of web-technologies in SCM. Further, organizational factors such as centralization and formalization in the IT unit structure and high levels of managerial IT knowledge were found to be significant antecedents of web-technology diffusion in the SCM function.