Article bred to apartir of the work of conclusion of course for attainment of heading of Bachelor in Civil Engineering SUMMARY The pathology can be understood as the part of the engineering that studies the symptoms, the mechanisms, the causes and origins of the defects of the civil constructions, that is, is the study of the parts that compose the diagnosis of the problem. The present work has as objective to study theoretical beddings on the manifestation of the corrosion in armed concrete. Had the frequency with that it occurs and its harmful consequncias the structures, the corrosion of the armors can be considered the main pathological manifestation of the structure of armed concrete. Invariably, the corrosion can be verified when the layer of responsible concrete for the protection of the armors does not reach its objective. To increase the useful life of these structures, some traditional techniques are used to diagnosis the problem, as well as promoting the recovery of the same ones. Words – key: Diagnosis, armed Concrete, Corrosion of the armors.