Evidence of systemic inflammation, i.e., elevation of serum C-reactive protein, interleukin-6, and/or the erythrocyte sedimentation rate, is correlated to poorer prognosis of patients with renal cell carcinoma (RCC). Serum amyloid A (SAA) has been recognized mainly as acute-phase reactant. Serum SAA from 72 patients with RCC were examined. Thirty-eight of 72 patients with RCC had elevated SAA compared with 17 healthy donors. The disease specific survival rate was significantly lower in the elevated SAA group, and SAA level was shown to be an independent prognostic factor by univariate and multivariate analysis. Evaluation of serum SM level in RCC patients may be a useful prognostic indicator.