Serum C-reactive protein (CRP) levels were measured by nephelometry in 30 healthy subjects (controls) and in 99 patients with uncomplicated terminal uremia on conservative therapy (group 1, n = 30) or chronic hemodialysis (group 2, n = 69). Whereas there was no difference between controls and group 1, both the mean concentration of CRP and the incidence of elevated levels were significantly higher in group 2 in comparison with both controls and group 1. Moreover, the degree of increase in these patients was directly correlated with the duration of hemodialysis. The abnormality, therefore, is somehow related to chronic hemodialysis per se. From a practical standpoint, we concluded that this test cannot be recommended as an acute-phase reactant in this clinical setting.