An enterprise information system (EntIS) is a computer-based system that integrates all organizational units and processes. EntIS evolved from transaction processing systems and manufacturing resource planning systems. Popular drivers for adopting EntIS included Y2K issues and corporate mergers. Currently the largest vendors have billions in annual sales. Successful EntIS implementation requires significant costs, training, and consideration of technical, economic, and operational feasibility. The future of EntIS includes more external partnerships and a focus on web-based and user-friendly systems.