Inventory Model has been one of the important issues specially in recent years that need to be addressed to improve the complexity of the companies and business competitiveness. On the other hand, Decision Support Systems (DSS) that are a specific class of computerized information systems that supports business and organizational decision-making activities, can help decision makers especially inventory managers to compile useful information from raw data, documents, personal knowledge, and/or business models to identify and solve problems and make better decisions. In this Book, we focus more on the mathematical model and artificial intelligence for inventory by considering the concepts of Decision support systems in supply chain management. The proposed system in this book can help managers in forecasting item demand in future, and also it can assist managers in order to choose an appropriate model which capable of determining the optimal order quantity and frequency of ordering based on the demand.