We have studied the serum ceruloplasmin levels as a possible diagnostic factor or marker for detection, diagnosis and follow-up of patients with melanoma. Ceruloplasmin concentration was determined in 64 melanoma patients (MP) and in 37 healthy persons (HP) by nephelometry. We found a mean value of 29.85 +/- 5.47 mg/dl in MP and 26.10 +/- 5.22 mg/dl in HP. A significant increase in the levels of serum ceruloplasmin was observed in MP in comparison to those in HP (P = 0.0011). In order to check whether this test could discriminate between MP and HP, a complete statistical Receiver Operating Characteristic (ROC) curve analysis was performed. The cut-off value was 25.10 mg/dl. The area under the curve was 0.689. According to these results, the test could discriminate adequately between the two groups.