For analysis of prognostic factors the clinical course of 109 patients with multiple myeloma was evaluated. Survival curves of immunoglobulin (Ig)G- and IgA-myelomas were identical (Fig. 1) with median survival times of 52 and 42 months, respectively, whereas patients with IgD- and Bence-Jones-myeloma had short survival times (median 3 months). Most important risk factors were anemia, renal insufficiency, and hypercalcemia (Figs. 7 and 8). Median survival time dropped from 52 months (Hb above 100 g/l) to 22 (Hb 85-100 g/l) and 1 month (Hb below 85 g/l). Patients with serum creatinine values below 2 mg/dl lived significantly longer than those with values above. Median survival times were 52 and 1 month, respectively. All seven hypercalcemic patients had a renal insufficiency and were in a very poor condition; their median survival time was 1 month. Analysis of the widely used staging system of Durie and Salmon gave disappointing results. Survival curves of the three A-stages ran close together with median survival times of 58, 51, and 36 months. Only the A-B classification according to renal function (A: creatinine under 2 mg/dl; B: creatinine above 2 mg/dl) proved prognostically relevant.