The pretreatment characteristics of 265 multiple myeloma patients treated between 1977 and 1983 were evaluated as potential prognostic factors for survival. Patients whose diagnosis was based on bone marrow plasmacytosis (greater than 30%) were noticed to have poorer survival (P less than 0.001). Although classification of patients according to stage has traditionally been used to identify prognostic groups, differences in survival were noted only between Stage III and Stage I or II patients using one of two common staging systems. Multivariate analysis using Cox's proportional hazards model identified the following prognostic factors in order of importance: plasmacytosis (hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.49 to 3.27), hypercalcemia (HR = 1.68, CI = 1.22 to 2.32), hypoalbuminemia (HR = 1.51, CI = 1.15 to 1.99), alkaline phosphatase (HR = 1.62, CI = 1.18 to 2.23), hyperuricemia (HR = 1.46, CI = 1.09 to 1.96), and renal insufficiency (HR = 1.48, CI = 1.08 to 2.04). All patients were followed from 2 to 7.5 years and 130 (49%) survived over 2 years. Logistic regression analysis demonstrated that hyperuricemia, hypoalbuminemia, renal insufficiency, plasmacytosis, gender, alkaline phosphatase, and hypercalcemia were significant predictors of 2-year survival. Knowledge of these factors could be of value in predicting prognosis and planning therapy in patients with multiple myeloma.