Chronic lymphocytic leukemia (CLL) is much less prevalent in Taiwan than in the West, but we have recently addressed the distinctly increasing incidence of CLL in Taiwan. We sought to find out whether there is any difference in cytogenetic abnormalities (CA) of CLL between the West and the East. We analyze the CA, by conventional cytogenetics (CG) and fluorescence in situ hybridization (FISH), and their clinical significance in 83 Taiwanese CLL patients and compared the data to those of Western countries. Thirty-five patients (42.2 %) possessed CG-CA and 58 (69.9 %) FISH-CA. By either CG or FISH, deletion of 17p or 11q was associated with poorer overall survival (OS) (P<0.001 and P=0.008, respectively), whereas isolated 13q deletion was associated with better OS (P=0.050). Trisomy 3 by CG was found in five patients; all of them were in Binet A stage but had strikingly poor OS (P<0.001). This prognostic impact was independent from the other CA and Binet stages. We conclude that, though the disease incidence is much different, the CA of CLL in Taiwan are similar to those in the West. The combined CG and FISH analysis is able to predict the patients' prognosis. The clinical significance of trisomy 3 warrants further validation.