Levels of copper, haptoglobin, fibrinogen and Factor VIII were measured in 30 patients with non-Hodgkin's lymphoma on 90 occasions in an attempt to demonstrate a possible correlation between hypercupremia and other acute phase reactants. The four parameters were measured simultaneously in active disease and in remission. The serum copper, along with other parameters, was significantly elevated in the active disease (P less than 0.001) and there was a high correlation between the levels of serum copper, fibrinogen and haptoglobin (P less than 0.001).