The aim of the paper was to analyze the microstructure of the welded joint of the Corten steel grade S355J0WP (base metal, heat-affected zone and weld metal). The oxid layer on the base material and oxid layer in the weld area on samples that were exposed to atmospheric influence in the rural, industrial and marine environment for 200 days was also analyzed and compared. Theoretical part of the paper describes general structural steels, and forms and types of corrosion. Special emphasis was placed on steels with increased resistance to atmospheric corrosion. In this part, types of Corten steel, the formation of an oxide layer on the surface, welding processes and application areas were described. In the experimental part, the results obtained by visual inspection of corroded surfaces, results of chemical composition analysis, microstructure analysis, EDS analysis and static tensile test results are presented. It has been shown that the type of atmosphere has a great influence on the corrosion intensity and the quality of the oxide layers formed on the Corten steel surface. The thinnest oxide layer and the most uniform surface coverage of corrosion products was achieved in the rural atmosphere, with the lowest homogeneity and the greatest depth of corrosion in the marine atmosphere.