Early and late transition metal single-site catalysts revolutionised the polyolefin manufacturing industry and research with their ability to make polymers with uniform microstructural properties. Several of these catalysts are currently used commercially to produce commodity and differentiated-commodity resins. The key to their rapid success and industrial implementation resided in the fact that they could be used without major modifications in the polymerisation reactors that previously used heterogeneous ZieglerNatta and Phillips catalysts. Since most of these industrial processes use slurry or gas-phase reactors, the soluble single-site catalysts must be supported on adequate carriers that ensure not only high activity, but also the formation of polymer particles with the proper morphology and bulk densities. In this article, we will review several methods used for supporting single-site early and late transition metal catalysts on a variety of supports. (C) 2011 Canadian Society for Chemical Engineering