To identify possible interracial differences in the behavior of multiple myeloma, the records of 52 black myeloma patients at Harlem Hospital Center (HHC) and 46 black and 46 white patients at Columbia-Presbyterian Medical Center (CPMC) were reviewed. In addition to clinical variables such as tumor burden, azotemia, and hypoalbuminemia, the effect of poverty on prognosis was examined, using socioeconomic indices from the United States census block group data of each patient. The median survival of CPMC black and white patients was comparable (34 and 29 months, respectively) whereas that of the HHC group was 12 months (Breslow test, P less than 0.0001). Overcrowding and hypoalbuminemia were the most significant prognostic factors by multivariate regression analysis on all 144 patients (P = 0.001); for HHC patients, overcrowding was the single significant variable affecting survival (P = 0.004). By all socioeconomic indices, HHC patients were more impoverished than CPMC patients (P less than 0.001); they also presented with more advanced disease. Race is not a significant prognostic factor in myeloma, whereas the effect of socioeconomic status on survival appears to equal that of previously described clinical features.