This Research Studies a Case Where There Are Twomanufacturers Producing Competing Products and Selling Them Through a Commonretailer. the Consumer Demand Depends on Two Factors: (1) Retail Price, and (2)Service Level Provided By the Manufacturer. Game-Theoretic Framework Is Appliedto Obtained the Equilibrium Solutions For Every Entities. In This Paper, We Develop a Game Theoretic Model Forcooperative Advertising In a Supply Chain Consisting of a Monopolisticmanufacturer Selling Its Product to the Consumer Only Through Competingduopolistic Retailers. We Consider a New Form of the Demand Function Which Isan Additive Form. the Demand Is Influenced By Both Retail Price and Advertisingexpenditures. We Develop a Pricecompetition Model For a New Supply Chain That Competes In a Market Comprised Ofsome Rival Supply Chains. the New Supply Chain Has One Risk-Neutralmanufacturer and One Risk-Averse Retailer In Which the Manufacturer Is a Leaderand Retailer Is a Follower.