Biopesticides, pest control products based on microbes or their bioactive compounds, are a growing segment of the biocontrol market, including those targeting insects. Biopesticides, including those targeting plant diseases and weeds, currently comprise ~10% of the total pesticide market, with bioinsecticides making up 30% of the biopesticides sold. That is still a low overall market share, considering the unprecedented need for environmentally friendly products with low mammalian toxicity. Despite consumer, grower and political declarations calling for more use, biopesticides continue to only grow at a steady rate year after year, although the growth rate is increasing compared to agrochemicals. This Chapter explores the issues around commercialising promising microbes into formulated biopesticide products and discusses areas where improvements may create more rapid advances their use.