Summary: This paper considers a buyer’s procuring strategy where the buyer purchases products from a supplier in order to minimize his total cost. Assume that the customer arrivals follow a Poisson process, a base-stock policy is implemented by the buyer, and the supplier will afford partial operating cost incurred by the buyer. The cost shared by the buyer includes procuring cost and some operating cost. The supplier does not hold the inventory and her production time is exponentially distributed. The objective of the supplier is to maximize her profit. The buyer designs a contract to minimize his total expected cost. Two different cases are considered: One potential supplier and many competing suppliers. The optimal control approaches are used to design the buyer’s optimal mechanism and some simple procurement mechanisms are presented.