Algae-derived products are already on the market, and more are entering the market every year. The expertise being developed through this commercial application, being combined with on-going academic research, will be critical to the eventual development of very large-scale commercial microalgal biorefineries. These refineries may or may not be primarily focused on the production of renewable biofuels; however, it is most likely that all will generate a portfolio of microalgae-based bioproducts that will include biofuels in order to make full use of the biomass generated. This chapter gives an overview of current and developing microalgal products, a discussion of the impact of commercial-scale microalgal biorefinery success on the variety of microalgae-derived bioproducts and the challenges facing successful production of commercial-scale biorefineries. Microalgae will play a valuable role in the development of sustainable and environmentally friendly bioproducts and biomaterials in the near future.