Abstract: The invention relates to a process for producing an organo-mineral fertilizer from vinasse, filter cake and generally boiler ashes, as byproducts of the sugar and/or alcohol manufacture and, optionally, complemented with fertilizer sources composed of macronutrients (primary and secondary) and micronutrients. The process comprises, in a preferred form of the invention, the steps of: concentrating the vinasse until about 65% of solids (p/p); mixing and dissolving the fertilizer elements in the concentrated vinasse; mixing and drying the filter cake and ashes in a hot gas stream obtained by burning bagasse or fine straw; impregnating this dry mixture with the concentrated vinasse mixture and the added fertilizer agents; and, finally, drying and granulating the final formulated mixture. The end product is a granular solid containing N, P, K, Ca, S, Mg and micronutrients, according to the previously programmed formulation.