none An extensive survey of the Terai area of northeastern Uttar Pradesh, India, was conducted to find natural enemies of aphids and to determine their potential as biological control agents. In this area, 25 species of aphid were recorded on >78 species of food plants. Among these, 21 species belonged to Aphididae, 1 to Drepanosiphinae, 2 to Greenidinae and 1 to Pemphigidae. Aphis craccivora, A. gossypii, Melanaphis sacchari, Rhopalosiphum maidis, Schizaphis graminum, Lipaphis erysimi, Macrosiphum miscanthi [Sitobion miscanthi] and Myzus persicae were categorised as pests of several crops such as Brassica spp., Dolichos lablab [Lablab purpureus], Cajanus cajan [pigeon peas], Cucurbita maxima, Lagenaria vulgaris [L. siceraria], Raphanus sativus [radishes], Pennisetum glaucum [pearl millet] and Zea mays [maize]. Few aphid species are reported in the area for the first time. The majority of parasitoids (which included Trioxys indicus, Lipolexis scutellaris, Lysiphlebia mirzai, Lysiphlebus delhiensis and Aphidius uzbekistanicus) were polyphagous and varied greatly in the rate of parasitization of one or more aphid hosts. The biological control potential of T. indicus, L. mirzai and L. delhiensis is known, whereas L. scutellaris is a little-known species. Six species of aphid hyperparasitoids were recorded, including Alloxysta pleuralis and Phaenoglyphis sp.