This paper presents a novel procedure for the chemical synthesis of a melamine-formaldehyde resin, modified by sulfonation with sulfanilic acid. The product was characterized by chemical analysis, FTIR spectroscopy and gel-permeation chromatography (GPC). Experimental data confirmed the obtaining of three oligomeric fractions of the melamine-formaldehyde polycondensate class, with potential uses as pretanning agent in the manufacture of bovine wet-white leather. The tanning potential of the obtained resin was assessed through the shrinking temperature of the tanned bovine pelt. An increase of the shrinking temperature by 8-10 degrees C was recorded on the pretanned leather, compared with the pelt, when the resin was used alone, while when used along with resorcine, an increase by 30 degrees C of the shrinking temperature was recorded.