This study focused on inventory management inpharmaceutical industry. For this purpose a Decision Support System for inventory management is designed in one of the major distribution channels in the Turkish pharmaceutical sector. In pharmaceutical sector n early all firms offer temporary sale prices for some products in certain parts of the year and wareh ouses usually want to purchase large amounts to use this offer. In case of temporary selling price to be asked how much quantity should be ordered to minimize total annual cost. For this purpose, the d esigned system helps decision maker in purchase decision