A rubber composition based on at least (i) an elastomer, (ii) a reinforcing filler and (iii) a thiouronium salt or an analogue of a thiouronium salt of the formula (I) below: A-S--Y--S-A (I) in which, A represents a group ##STR00001## associated respectively with a molecule HX or an ion X--, X denoting a halogen atom and Z denoting ##STR00002## Incorporating the thiouronium salt into the vulcanizable rubber composition makes it possible to substantially reduce the reversion rate of the vulcanized rubber composition.