The Lecce limestone, a highly propus calcarenite of biological origin, undergoes severe deterioration processes which are mainly determined by the large amounts of soluble salts (sodium sulphate and mitrate, with smaller smounts of chlorides) present on the surface and inside the stone. As all attempts to remove them completely by extraction processes result in heavy losses of surface material, it is necessary to proceed to a consolidation treatment in the presence of salts. In order to evaluate the efficiency of five types of consolidants, when applied in such conditions, several cubic samples of Lecce limestone were impregnated with a salt solution before treatment, and then submitted to severe crystallization cycles after treatment.