Two alloys of selected chemical compositions of the CoCrFeMnNi family characterized by a high mechanical resistance have been prepared by melting and thermomechanical treatment. Laboratory cold crucible casted alloys with ultra-high purity have been compared to VIM ingots with typical industrial residuals (O, N, C, S, P).. The ingots have been processed by forging or rolling (hot or cold). For both modes of melting, a single phase FCC structure has been obtained. For a constant mode of thermomechanical treatment, both microstructure and mechanical properties (YS, UTS, elongation to fracture, at room temperature and liquid nitrogen temperature) are only slightly sensitive to the melting mode and therefore, to the presence of industrially unavoidable impurities.