This study presents the results of testing for resilient modulus and permanent deformation to evaluate the mechanical properties of a soil stabilized with fly ash from municipal solid waste incineration. The soil tested is a non-lateritic clayey soil, which is not suitable for use in pavement works. The addition of fly ash improved reduced its expansibility and modify their mechanical properties, these being dependent on the MSW fly ash content, moisture and number of load cycles. A paving project was implemented to assess their competitiveness as a base material for pavements. The results of this project showed that soil stabilized with fly ash is competitive for low volume traffic roads, with the advantages of minimizing the environmental problems caused by solid waste disposal and waste incineration.