Abstract: A rubber composition which can be used in particular in tires, based on at least one diene elastomer, one reinforcing filler, one crosslinking system, one phenolic resin and one polyaldehyde. The use of a polyaldehyde makes it possible to advantageously replace conventional methylene donors while preventing the production of formaldehyde during the vulcanization of the rubber compositions and thus to limit the environmental impact of these compounds. Furthermore, these polyaldehyde compounds make it possible not only to obtain rubber compositions exhibiting the same low-strain stiffness as conventional rubber compositions using HMT or H3M methylene donors but also, surprisingly, to greatly improve the fatigue strength of the rubber compositions and thus the endurance of the tires.