Recent publications suggest that tyrosinase mRNA in blood as well as in bone marrow is detectable only in a subgroup of patients with metastatic melanoma. This would imply that tyrosinase mRNA is of limited value as a tumor marker. We addressed the question of whether patients with metastatic melanoma and RT-PCR-detectable tyrosinase mRNA in blood or bone marrow have a different prognosis than tyrosinase mRNA-negative patients. Twenty melanoma patients with widespread clinical metastases were enrolled; the survival time after first diagnosis of visceral metastases was correlated to tyrosinase mRNA presence in blood and bone marrow samples. The time of survival of eight patients with metastatic melanoma and detectable tyrosinase mRNA in either blood or bone marrow was not different from the prognosis of 12 patients without detectable tyrosinase mRNA in either blood or bone marrow. Detection of tyrosinase mRNA in blood or bone marrow samples of melanoma patients with advanced disease seems to have no substantial relevance for survival time and outcome of disease. In this constellation, detection of tyrosinase mRNA by RT-PCR is not a valid tumor marker. Nevertheless, tyrosinase positivity in bone marrow in earlier tumor stages might indicate increased risk for the development of distant metastases. This should be addressed in further studies.