Feed is the foremost and highest expense in large-scale breeding of monogastric animals, accounting for more than 70% of the total production costs. For more than 30 years, various enzymes have been used to improve the efficiency of feedstuff utilization. These enzymes are applied to simultaneously address many different practical problems in feed use, such as reducing the presence of antinutritional factors, increasing the digestibility of feed constituents, reducing the viscosity in the digestive tract, allowing the use of low-cost ingredients, and reducing environmental risks related to manure and waste disposal. The main feed enzymes in the market are phytases, xylanases and β-glucanases (cellulases). Nevertheless, other enzymes, such as mannanases, α-galactosidases, pectinases, amylases and proteases, are increasing in use. Poultry and swine sectors are the main feed enzyme consumers; however, ruminants, aquaculture and pets are projected to be large markets in the near future. Recent and future advancements in this field of knowledge are discussed here.