Background Chromosomal abnormalities have been shown to play an important prognostic role in multiple myeloma (MM). Interphase fluorescence in situ hybridization (i-FISH) has been much more effective to identify cytogenetic aberrations in MM than conventional cytogenetic technique (CC). To clearly determine the cytogenetic features of Chinese MM patients and identify their prognostic implications, we designed a multicenter study based on i-FISH including 672 patients from 52 hospitals in China. Methods All 672 patients were systematically screened for the following genomic aberrations: del(13q), IgH rearrangement, del(p53) and 1q21 amplifications. Results The analysis showed that the chromosomal changes were detected in 22.1% patients by CC and in 82.3% patients by i-FISH. The most common abnormalities by CC were chromosome 1 aberrations (48.4%), -13/13q- (37.6%), hyperdiploidy (36.6%), hypodiploidy (30.1%) and IgH rearrangements (23.7%). The most frequent abnormalities by FISH was del(13q), which was found in 60.4% patients, whereas IgH rearrangement, 1q21 amplification and p53 deletions were detected in 57.6%, 49.0% and 34.7% cases, respectively. By statistical analysis, -13/13q- by CC was associated with low level of platelet (P=0.015), hyperdiploidy was associated with low level of serum albumin (P=0.028), and IgH rearrangement by FISH was associated with high level of 82 microglobulin (P=0.019). Moreover, 1q21 amplification and del(p53) by FISH conferred a high incidence of progressive disease (PD) after initial therapy. Metaphase detection of IgH rearrangements and chromosome 1 aberrations concurrently was associated with a short progression free survival (PFS) (P=0.036). No significant prognostic implications of other cytogenetic abnormalities were found associated with overall survival and PFS. Conclusions Chinese MM patients had similar cytogenetic abnormalities compared with the previous reported studies. However, the prognostic significance of FISH aberrations were not clearly determined and further study is required. Chin Med J 2012;125(15):2663-2670