The Nilgiris in Indian subcontinent is one of themajor Biodiversity hot spot in India and renowned for the endemism. Crucifers are the imperative cash crops cultivated in various parts of this high altitude. Insect pests diversity associated with cruciferous crops were evaluated at four different sample sites in Nilgiris district. Thirteen species of cruciferous crop pests belong to four orders such as, Lepidoptera, Homoptera, Coleopteran, and Hemiptera were recorded. Highest number of individuals was recorded in Lepidoptera and lowest number of species in Coleopteran andHemiptera.Among the families, aphididae (Homoptera) was dominant followed by plutellidae, pyraustidae and noctuidae (Lepidoptera). Among the species, Lipaphis erysimi (Homoptera: aphididae) was eudominant, Plutella xylostella (Lepidoptera: plutellidae) was dominant and other species were subdominant, recedent, subrecedent. Total number of cruciferous insects found declined from October to December and there after a steady increase was observed up to March. However, such a variation was not observed in terms of species composition and diversity.