The effect of polymeric coatings on concrete protection against chemically aggressive environments was evaluated. Two polymers - acrylic and epoxy - were applied on different concretes. The protection was measured by tests related with chemical resistance. The chlorides penetration, sulphates, acids and bases attack tests were used. Surface treatments act as a barrier between the environment and the concrete. This work intends to contribute to a better understanding of the performance of coated concrete in chemically aggressive environments, by presenting results of ion diffusion and resistance to aggressive solutions of several coatings used to protect concrete. The performance of the used coated concretes against chemically aggressive environments was generally better than the performance of the unprotected concretes. The results indicate that the overall performance of the used epoxy resin was better than that of other used coatings.