The objective of this work was to evaluate the rate of gene flow between GM (RR) and conventional soybeans, in the city of Alfenas, in the south region of Minas Gerais State, Brazil. The work was carried out in the Horticultural Section and Experimentation of the University Jose do Rosario Vellano - UNIFENAS, in the period of October of 2004 trougth November of 2005. It were been used two cultivars of soybeans (Glicine max): one traditional cultivar MG/BR 46 (Conquista), not tolerant to the glyphosate, and other cultivar (BRS Valiosa) resistant to the molecule from glyphosate. The experimental area was delineated by sowing in concentric circles with rays of 1, 2, 3, 4 m for the plant of the cultivar not genetically modified (Conquista) and 5 m for the plants of the cultivar genetically modified. Plants removed of both the populations had received an application from glyphosate, by the applications of the commercial product Roundup, in the dosis of 1.0 L.ha-1 when they had reached the V3 stadium, with the objective of certification of the resistance to the herbicide. The RR gene flow in soybeans occurs at low taxes (maximum of 0.25%) in the conditions of Alfenas - MG, Brazil. However, these fact indicates a potential of contamination in soybeans plants not genetically modified growing near the RR plants.