Operations research is the application of scientific methods, techniques and tools to problems involving the operations of a system so as to provide those in control of the operations with optimum solutions to the problems. The term inventory refers to any kind of resource having economic value and is maintained to fulfil the present and future needs of an organization. Since the late 1940‟s inventory theory has been one of the most successful operational research techniques to be applied in business, industry and in public sector. As the customer is the best advertisement, the success of any trade depends on the customer‟s satisfaction. Without any inventory in an enterprise it can‟t function smoothly. It is essential to balance the advantage of having inventory of resources and the cost of maintaining it and determine an optimal level of inventory of each resource so that total inventory cost is near its minimum. Decisions regarding how much and when to order are significant in every inventory problem. Inventory has been viewed as a necessary evil that cannot be eliminated. It is termed as demon because maintaining inventory ties up money which could have been used for alternative purposes and also increases carrying cost. Thus the control and maintenance of inventories of all goods are common problems to all enterprises in any section of economy. Mathematical models can help in providing the solution to manage inventory.