Melanogens which are considered as probable precursors or their metabolites in the metabolic pathway toward melanin are excreted in an increasing amount during the melanotic melanoma growth in hamsters. Moreover, an increased excretion of zinc was observed. The evaluation of dependence between zinc and Thormählen positive melanogens excretions during the melanoma growth suggests an exponential type of dependence. Likewise as in the case of human melanoma the hyperzincuria proved to be a laboratory sign of tumor disease progression in Syrian hamsters as well. The cause of an increased zinc excretion during the melanoma growth seems to consist in an increased lysis of pigment cells. The presumed destruction of tumor cells was not accompanied by a higher excretion of magnesium, though. Concentration of creatinine proved to be a useful mean for expressing of standard excretion of various substances also in hamsters.