Steel corrosion is one of the main causes of damage in reinforced concrete structures. Recent studies carried out in Argentina indicate that the percentage of damage in concrete structures induced by corrosion of reinforcement is 16%. In structures located in marine environments the corrosion is due fundamentally to the action of chlorides. Chlorides penetrate concrete by different processes; in structures exposed to atmosphere, the ingress process is by diffusion. Ingress depends on the characteristics of concrete and of its distance to the sea (marine environment). In this paper, assessment of durability of concrete structures exposed to marine (Atlantic Ocean coast) environments is reported. The ages of the evaluated structures, bridges and buildings, vary between ﬁve and 67 years. Surface chlorides concentration (environmental loads) and the effective diffusion coefﬁcient, calculated using Fick’s second law, are included. Furthermore, the quality of the cover concrete is characterised by means of the speciﬁc gravity and porosity accessible to water methods.