—MIMO links can significantly improve network throughput by supporting multiple concurrent data streams between a pair of nodes and suppressing wireless interference. In this paper, we formally define a new cross-layer optimization problem for MIMO-based multihop wireless networks, which is referred to as the joint Stream Control and Scheduling Problem (SCSP). We first present a constant factor approximation algorithm to solve the SCSP. In addition, we present a heuristic algorithm to improve the performance further, which is shown to be efficient in practice by our numerical results.