Interleukin-6 (IL-6) and acute phase proteins are commonly increased in patients with multiple myeloma. Several of these acute phase proteins are believed to predict prognosis and influence survival. We measured interleukin-6 (IL-6), C-reactive protein (CRP), alpha-1-antitrypsin (a1AT), acid alpha-1-glycoprotein (a1AG), haptoglobin (HAP), transferrin (TRF), hemoglobin (Hb), beta-2-microglobulin (beta2M) and erythrocyte sedimentation rate (ESR) in 42 newly diagnosed multiple myeloma patients and 25 normal controls. At the time of blood collection, nine patients were at stage I of disease, 14 at stage II, and 19 at stage III according to the Durie and Salmon myeloma staging system. Mean +/- SD values of IL-6, CRP, a1AT, a1AG, HAP, beta2M, and ESR were significantly higher and Hb significantly lower than those found in the controls. Univariate analysis, using the log-rank test, showed that among the acute phase proteins, serum CRP (P < 0.002), a1AT (P < 0.008) and ESR (P < 0.008) were significantly correlated with survival. However, when a multivariate Cox proportional hazard model was performed, ESR, CRP, a1AT, a1AG and beta2M were identified as independent prognostic factors, while the others were not. We conclude that ESR, a simple and easily performed marker, was found to be an independent prognostic factor for survival in patients with multiple myeloma.