Concrete test specimens containing galvanized and black reinforcing steel were partially immersed in saturated salt solution. The results were that a) corrosion began at about the same time for both the galvanized and black (mild) steel exposed in the same concrete system; b) the greater the thickness of zinc was, the earlier concrete cracking occurred; and c) in concrete of high quality, galvanized steel caused cracking earlier than black steel. Observations indicate that galvanizing is either inefficient or ineffective in preventing rusting of underlying steel in concrete. Most significant in postponing concrete cracking caused by corrosion of black or galvanized steel was increasing the cement factor. There does not appear to be a half-cell potential value per se that discloses the corrosion activity of galvanized steel in concrete.