We report the new functionality of room temperature ferromagnetism in CuO-ZnO heterostructures. Magnetic measurement results indicate the CuO-ZnO heterostructures show enhanced ferromagnetism contrary to the pure CuO (ZnO) and the observed ferromagnetism is proportional to the interface counts for the film-heterostructures, providing proof of interface related ferromagnetism. Our study suggests that magnetically functional interfaces could be an entirely new and novel design of magnetic materials for emergent devices.