Our aim was to evaluate the clinical use of cytogenetic analysis as a prognostic factor in the outcome of newly diagnosed multiple myeloma (MM) patients. The present series includes 111 newly diagnosed MM patients treated with one of three standard-dose regimens or autologous transplantation over an 8-year time interval. As expected, the presence of an abnormal karyotype (39% of patients) correlated with poor prognosis (progression rate 63% v 47%, P = 0.042), shorter event-free (EFS, P = 0.014) and overall (OS, P = 0.005) survival. Two distinct cytogenetic abnormalities were the most significant variables that influenced EFS and OS in the univariate analysis. The presence of hypodiploid karyotypes or rearrangements of band 22q11 were associated with higher progression rate (P = 0.001) and shorter EFS (P < 0.024) and OS (P < 0.004). The median EFS and OS for patients with hypodiploidy was 4 and 7 months respectively. Multivariate analysis showed that absence of hypodiploidy was the most favourable prognostic variable for OS (P = 0.022) followed by stage < or = IIA, serum calcium < or = 2875 micromol/l, and absence of abnormalities 22q. The data suggest that the presence of hypodiploid karyotypes and rearrangements on 22q11 band show a higher progression rate and shorter survival in MM patients.