We show a new way through which patent protection affects innovation. We show that patent protection may reduce the final goods producers' incentives for innovation in industries with imperfectly competitive input markets. The input market structure may play an important role in this respect.

We show the impact of technology licensing on optimal patent policy. Strong patent protection that eliminates imitation may not be the equilibrium outcome in the presence of licensing. Depending on the cost of innovation, licensing may either increase or reduce the strength of the patent protection.