For the past 30+ years, the black soldier fly Hermetia illucens (L.) (Diptera: Calliphoridae) has been studied intensively as a means for addressing two issues of global concern: organic waste management, and alternate protein production. The larvae are voracious, generalist feeders, able to consume a wide variety of materials ranging from plant matter (fruits, vegetables, grains, etc.) to animal matter (tissue, manure, etc.), and transform these materials into body mass that can be upwards of 45% protein and 35% fat. Additionally, this is the only insect species that has been approved for use as an animal feed in the United States (for salmonid fish) and Canada (for salmonid fish and broiler poultry). Maintaining a robust population to supply an operation with the larvae necessary for waste management and protein production is of utmost importance for entities interested in mass producing black soldier flies, while at the same time ensuring consistent larval output (in both quantity and quality). This chapter focuses on methods used for rearing black soldier flies, as well as challenges associated with mass production for waste management and protein production.