Multiple myeloma (MM) is a malignant proliferation of bone marrow plasma cells. Molecular analyses of the involvement of oncogenes (c-myc, and N- and K-ras genes) and suppressor gene (p53) in pathogenesis of MM have been recently carried out. Relatively high incidence of elevated expression of c-myc mRNA have been found, although the gene rearrangements are very rare. Mutations of N- and K-ras genes have been found in about 1/3 of patients with MM. Point mutations of p53 gene were detected in about 10-20% of patients. The mutations were found in terminal or leukemic phase of the disease. These indicate that oncogenes and suppressor genes are involved in the development and progression of MM.