The production of a homogeneous protein sample in sufficient quantities is an essential prerequisite not only for structural investigations but represents also a rate-limiting step for many functional studies. In the cell, a large fraction of eukaryotic proteins exists as large multicomponent assemblies with many subunits, which act in concert to catalyze specific activities. Many of these complexes cannot be obtained from endogenous source material, so recombinant expression and reconstitution are then required to overcome this bottleneck. This chapter describes current strategies and protocols for the efficient production of multiprotein complexes in large quantities and of high quality, using the baculovirus/insect cell expression system.