Aluminum in the solid phase is a normal part of every soil. However, in solution aluminum is toxic to plants at low concentrations. It is the third most abundant element in the earth's crust and a formidable phytotoxic barrier to crop production in acidic soils (40% of the world's arable lands). The major reaction involved in Al toxicity is aluminum hydrolysis. Leguminous plants and their dinitrogen fixing symbionts like soybeans and Bradyrhizobium are particularly acidifying because the anion/cation uptake from the soil is more imbalanced toward cations than is uptake by non-leguminous nitrate assimilating plants. The major Al toxicity symptom observed in soybean plants is inhibition of root growth. Lateral roots become thickened and turn brown. Under field conditions it is often difficult to observe root systems. In soybean, practical breeding for Al tolerance has been limited by inadequate screening methodologies. In our experiment, 100 recombinant inbred lines (RILs) of soybean with ‘Forrest' and ‘Essex' as their parents were sown in sand media. After three weeks, root length was estimated using simple scale method (Hypocotyl to root tip) & Newman's direct intercept method. Plants were moved to hydroponics. The pH of the media in the growth chamber (AR-75L) was regulated by addition of sulphuric acid for a pH of 4.2. Plants were shifted to aluminum stress (2µmoles/litre). After 72 hours and root length was observed again. Preliminary results indicated the toxicity of Al at this concentration. Essex was more resistant than ‘Forrest'. There were transgressive segregants. Genetic mapping showed the Quantitative Trait Loci (QTL) underlying resistance to Al toxicity were on LG C2 and N. They were linked to or pleiotropic with loci underlying disease resistance and other root traits. Candidate genes were identified in SoyGD.