In the search for new, cheaper and environmentally sustainable sources of protein-rich food, much research has shown the alternative role that insects could play in animal feed. Fly larvae or maggots have been identified as a food source that is very rich in protein, dietary fat, vitamins and minerals. The most commonly used maggots in animal feed are those of the housefly (Musca domestica L. 1758) and the black soldier fly (Hermetia illucens L. 1758). Different maggot production systems for these two fly species have been developed and others are still being developed in different contexts around the world. The production of these maggots does not require much expenditure as they can be easily obtained from animal and/or plant waste available free of charge or at low cost. This study summarizes the available literature on the methods of production of maggots of these two fly species and their use in animal feed. Also, the zootechnical performance of animals fed with maggots and the importance of maggots were discussed in this study.