The West Indian Fruit Fly, Anastrepha obliqua, a serious pest of mangoes in St. Kitts, causes heavy crop losses and makes the fruit unmarketable to other Caribbean countries and the United States of America. Three unimproved mango varieties, "Round Ball" "long Ball" and "Sour Bath" are widely distributed In the island and harbour large populations of the pest. Of these, "Sour Bath" is most susceptible, with levels of infestation ranging from 0-100% (avg. 32%). At Wingfield under the Tree Crop Project, the Ministry of Agriculture has planted the varieties, Julie, Irwin, Graham, Haydon and Amory Polly. Some of these are also grown at Parsons Estate and Molyneux. As the unimproved mangoes grown all over the island, WIFF easily migrates to the grafted mangoes, causing heavy damage. Average levels of fruit infestation recorded were: Julie 4%, Haydon 71, Graham 12%, Irwin 15% and Amory Polly 17%. Because of the continued Influx of WIFF from wild mangoes, sanitation efforts made by the farmers is proving futile, although the levels of fruit damage on their farms is significantly lower. Three species of ptedators, Omalodes sp. nr. laevlgatus, Glyptolenus sp. and an unidentified species of a staphylinid were found feeding on the pest in the field. Omalodes was most common throughout the island. During these studies no parasite was recorded. It is therefore suggested that where Anastrepha spp. are a serious problem, a long term biological control programme may be organized, in which Important exotic parasites may be obtained and released against it.