A resin in the H+ form (Dowex 50W-X8) was used to extract fulvic acids from a Spodic horizon. This resin has the following advantages in relation to the reagents normally used. It solubilizes organic matter while purifying it and without altering it by oxidation and hydrolysis. Furthermore, since the resin is eliminated completely from the extract, no contaminating ions remain. The soil was agitated in a mixture of water and resin. The extract obtained was filtered, centrifuged, purified by passage through a column of H+ resin and freeze-dried. The alternation of freeze-drying and resolubilization resulted in the coagulation of the silica which was removed by centrifugation. Acid organic matter with very low ash content (1%) was obtained. The fulvic acids extracted by resin and by Na-pyrophosphate were compared. Qualitatively they were practically the same, as evidenced by the similarity of the curves obtained by gel-filtration (Sephadex). Quantitatively the resin, however, was a more efficient reagent. Therefore, it is recommended for the extraction of fulvic acid and organo-mineral complexes.