The objective of this study was to verify application of two methodologies: substrate moistened with herbicide solution (SM) and immersion of seeds in herbicide solution (IH) for detecting soybean seeds genetically modified. For this, non-transgenic and transgenic soybean seeds, harvested in the 2008/2009 crop seasons were used. The treatments with substrate moistened were: SM1) 0.03% herbicide solution, at 25oC, with evaluation in the sixth day (hs -0.03% -25oC, 6thd); SM2) HS -0.03% -35oC, 5thd; SM3) HS -0.03% - 40oC, 5th
d; and SM4) hs -0.06% -5oC, 5thd. In the methodology of immersion of seeds the following treatments were performed: IH1) seed immersion in a 0.6% herbicide solution, at 25oC, for 1 h, (si -0.06% -25 ºC, 1 h; IH2) si -0.06% - 35oC, 30 min.; IH3) si -0.06% -40oC, 30 min.; IH4) si -0.12% -35oC, 30 min.; and IH5) si -0.12% -40oC,
30 min. Bioassays allow detecting soybean seeds tolerant to glyphosate herbicide within five days. The seeds of non-genetically
modified and genetically modified soybean cultivars may be easily distinguished through the treatments SM2 and SM4 of the moistened substrate methodology; and treatments IH3, IH4, and IH5 of seed immersion methodology. Both methodologies are easily feasible, practical, and applicable in seed analysis laboratories, once do not require special equipments.