The gene flow from commercial varieties of cotton to wild species have been studied under the context of environmental risk analysis of GM cotton. Due the role of the bees in the pollen transportation among cotton plants and the possible impacts of the Bt toxin on these species, it was conducted an inventory of flower visitors in different species and different production regions of Brazil during 2003, 2004 and 2005. Information about diversity and abundance of bees on flowers of cultivated species, Gossypium hirsutum and three different wild species of cotton was obtained. In all studied area it was used the large sampling plots method, methodology previously developed and tested in 2003 in the Federal District in a commercial farm cultivated with Gossypium hirsutum (var. Delta Opal). In 2003, the sampling was conducted in Campina Grande, PB on the wild species G. barbadense, G. mustelinum e G. hirsutum var. marie-galante and in Barbalha (CE) on G. hirsutum latifolium. In 2004 the sampling were repeated in the Federal District. The inventory on G. hirsutum latifolium were developed in 2005 in the states of Bahia (Barreiras), Mato Grosso (Primavera do Leste and Rondonópolis), Goiás (Santa Helena de Goiás, and Jussara) and São Paulo (Jaboticabal), and also extended to different areas in the Federal District. Also, in 2005, the studies on the wild species of cotton were conducted in the region of District Federal and northwest of Minas Gerais state. The studies on G. hirsutum latifolium were conducted on commercial farm with and without insecticide applications and also in the Embrapa experimental fields. The bees were the main flower visitors on cotton plants. Taking in account all studied areas, from 153 insect species collected on flowers, 47.40% (72 species) are from four families of bees and 49.78% (1,630) of the total number of individuals collected (3,274) are bees. One species of the genus Exomalopsis is a new species, undescribed in the literature. How was pr