Biological control is expected to become the basic pest control system in Japan for promoting safe crop production in greenhouses. Twelve arthropod natural enemy species and three fungus species have become available for commercial use in greenhouses. Imported species were commercialized first, with the commercial use of indigenous species coming later. The extreme temperature conditions in greenhouses, the delay of release, the effect of chemicals and the low level of tolerance for pest damage in some crops are major limiting factors in the use of natural enemies in commercial greenhouses. Among the indigenous Orius species, O. strigicollis has been commercialized to control thrips because of its low diapause incidence and the ease of mass production. A promising parthenogenetic strain of an indigenous eulophid species, Neochrysocharis formosa, has been found in Kyushu District and has shown a highly suppressive effect on Liriomyza trifolii in Okinawa. Cultural control measures, such as field hygiene or prevention of pest immigration, are fundamental for the effective control of pests. Since it is impossible to control all pest species with natural enemies, the integrated use of natural enemies and other control measures, which include cultural control and the use of selective pesticides, is essential for commercial application.