A new fruit fly species suspected to be from the Bactrocera dorsalis (Hendel) group (originating from Asia), was detected during routine field surveys in the Coast Province of Kenya. Since most species in this group are of tremendous quarantine concern when introduced, and considering the fact that it has never before been detected or reported in continental Africa, surveys were immediately initiated covering a distance of over 3000 km across major fruit-growing and trading localities within Kenya, to determine the extent of spread of the new invasive species. We report on the detection of the flies, preliminary results of the survey, and discuss the potential effects of these flies on the horticulture industry in East Africa.