The paper describes an inventory control problem related to optimization of processes that occur in supply chains with multiple alternative suppliers which have different degrees of reliability and different econometric characteristics. Two cases are considered: (a) fixed part of the delivery cost is the same for all suppliers and (b) all suppliers have various cost components. For case (a) algorithms for constructing optimal inventory control strategies and supplier selection are proposed. For case (b) a general scheme of optimal strategies construction is proposed. Simulation results are provided.