Industrialised rearing of house flies and black soldier flies in systems for producing protein offers numerous species-specific benefits and challenges. These two dipteran species offer great potential for mass production of protein rich feed ingredients on a global scale. Through this systematic review, various facets of intensive production of these species are evaluated according to criteria, such as development time, abiotic tolerance, ease of rearing, environmental impact, safety risks, range of possible organic side streams, and their role in bioconversion.