The prognostic significance of age, sex, ethnic origin and various laboratory data was studied retrospectively in 69 patients with multiple myeloma using conventional statistical tests and the multiple regression computerized analysis. The conventional statistical analysis confirmed that age, anemia, uremia, hypoalbuminemia, hyperglobulinemia, hyperuricemia and IgA lambda type myeloma were associated with a poor prognosis. The multiple regression analysis indicated that age and blood urea nitrogen levels were the only variables which significantly affect the survival of patients with multiple myeloma. A correlation was found between blood urea nitrogen levels and other laboratory data of apparent prognostic value. The differences between our results and those of other authors are discussed and it is suggested that they may, in part, be due to the fact that the interplay between the various prognostic variables was not exposed in other studies.