The preparation of organocopper reagents by transmetalation protocols has emerged as a versatile new tool for selective C,C-bond formation. In this review, the use of organoaluminum, -boron, -lead, -manganese, -mercury, -samarium, -stannane, -telluride, -titanium, -zinc, and -zirconocene derivatives for the preparation of copper complexes is presented and compared to traditional protocols originating from lithium or magnesium organometallics. Significantly, a wide range of functionality is generally tolerated in the transmetalation procedures, and the reactivity of the resulting cuprates depends on the presence of the residual metal salts. The use of these heterobimetallic cuprates in natural product synthesis demonstrates some of the key features of this new methodology. 1. Introduction 2. Transmetalations in the First Transition Metal Series: Titanium, Manganese 3. Transmetalations in the Second Transition Metal Series: Zirconium 4. Transmetalations in the Lanthanide Series: Samarium 5. Transmetalations in Group IIB: Zinc, Mercury 6. Transmetalations in Group IIIA: Boron, Aluminum 7. Transmetalations in Group IVA: Tin, Lead 8. Transmetalations in Group VIA: Tellurium 9. Applications to Natural Product Synthesis 10. Conclusions