The influence of manganese on the solidification process, on the shrinkage cavity formation, on the casting macro-and microstructure, and on the mechanical characteristics of cast copper-tin alloy (sand-, die-and continuous-casting) is analyzed. It was found that the addition of manganese influences primary dendritic solidification, and morphology of the alpha phase, amount of eutectoid, distribution of shrinkage phenomena, and mechanical properties. That effect depends mostly on the melting practice, and the cooling conditions of alloy. -- AATA