Cytogenetic data of 41 patients diagnosed with multiple myeloma (MM) are reported. In all samples, cytogenetic studies were made of short-term and B-cell-stimulated culture: 20 cases (48.8%) showed chromosome abnormalities; 14 karyotypes were hypo- or pseudodiploid, and six were hyperdiploid. The most frequent numerical changes affected chromosomes 7, 11, 5 (gains), 14, 20, and Y (losses). Chromosome structural rearrangements of 22q were noted in six patients. Other and recurrent cytogenetic abnormalities were changes involving chromosomes 1, 14, and 17. A significant relation was observed between presence of chromosome abnormalities and the following hematologic parameters: clinical stage III (p = 0.0212), bone marrow (BM) plasma cell infiltration greater than 30% (p = 0.0379), presence of bone lesions (p = 0.0051), and beta 2-microglobulin levels greater than 4,000 md/dl (p = 0.0194).