Process for the production of sugars from biomass derived from guayule plants comprising: subjecting said biomass to a biological pretreatment in the presence of at least one ligninolytic fungus obtaining a liquid phase comprising sugars and a first solid residue: subjecting said first solid residue to hydrolysis in the presence of at least one diluted inorganic acid obtaining a first hydrolysate comprising sugars and a second solid residue; subjecting said second solid residue to enzymatic hydrolysis obtaining a second hydrolysate comprising sugars and a third solid residue. The sugars thus obtained can be advantageously used as sources of carbon in fermentation processes for producing alcohols (e.g., ethanol, butanol), lipids, diols (e.g., 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol), or in chemical synthesis processes for producing other intermediates or chemical products (e.g., furfural). Said alcohols and lipids can be advantageously used in turn in the production of biofuels (e.g., biodiesel or “green diesel”), which can be used as such, or mixed with other fuels for transportation, while said diols can be used in the production of products such as bio-butadiene which can in turn be used for manufacturing rubbers (e.g., polybutadiene or copolymers thereof). Said uses are particularly important in the case of a biorefinery.