To study the relationship of Mediterranean fruit fly or medfly, Ceratitis capitata (Wiedemann), to native plant hosts in an area within its original home range, fruits were sampled in diverse areas of Kenya from 1999 to 2001. Sampling effort was concentrated in and around forested areas in coastal, central highland, and western highland habitats. Medflies were reared from fruits of 55 species of plants, 51 of them indigenous; 46 of these species represent previously unknown hosts in Africa. Fruits infested by C. capitata were collected in all study sites, east and west of the Gregory Rift Valley, in xeric habitats between the coast and the central highlands, and at altitudes from sea level to 2,164 m above sea level. The conditions for year-round breeding of medfly in indigenous fruits are present at the coast, and possibly in highland areas as well. Infestation indices were comparable to those reported elsewhere from cultivated fruits. Although polyphagous in its home range, C. capitata was not distributed uniformly among species within two important host-plant families, Sapotaceae and Rubiaceae.