B-cell chronic lymphocytic leukemia (CLL) is the most common type of adult leukemia in the Western countries, however, infrequent in the Eastern. It shows a remarkable heterogeneity, with some patients having an almost normal lifespan, others surviving only several years after diagnosis despite intensive therapy. To explore the prognostic significance of CD38 expression in Chinese patients with CLL, multi-parameter flow cytometry was used to detect the expression of CD38 on CD5+CD19+ cells of 147 patients. CD38 expression and its association with some other prognostic factors such as Binet stage, lymphocyte count in peripheral blood, serum lactate dehydrogenase (LDH), 2-microglobulin (2-MG), ZAP-70 expression and cytogenetic abnormalities were analyzed. The Kaplan-Meier method was used to construct survival curves, and results were compared using the log-rank test. Univariate and multivariate Cox regression analyses were used to assess associations between survival time and potential risk factors. Out of the 147 CLL patients, positive expression of CD38 was found in 45 (30.6%) cases. CD38-positivity identified a subgroup of CLL patients with aggressive disease of Binet stage at the time of the test (P=0.036). Furthermore, the presence of higher serum LDH and 2-MG levels at diagnosis was strongly correlated with CD38-positive (P=0.016 and 0.025, respectively). Prognostically unfavorable cytogenetic abnormalities, including 17p13 and 11q22 deletions, were significantly more frequent in CD38-positive patients than in CD38-negative ones (P=0.047 and 0.001, respectively). Therewas no significant difference between CD38-positive and CD38-negative groups in molecular cytogenetic aberrations of del(6q23), del(13q14), 14q32 translocation, or trisomy 12. In addition, in CD38-positive patients, the percentage of leukemic cells expressing ZAP-70 protein was not significantly higher than in CD38-negative ones (P=0.120). CD38 expression was associated with poor outcome. Patients with positive expression of CD38 had significantly shorter overall survival (mean, 81 months) than patients without CD38 expression (mean, 179 months) (P=0.015). Univariate analysis showed that serum levels of LDH and 2-MG, del(17p13) and CD38 expression were the significant factors in determining overall survival (OS). Del(17p13) and CD38 expression were the variables strongly associated with OS by multivariate Cox regression analysis. It was showed that the patients with high level of CD38 expression had poorer outcome; CD38 was a good predictor of OS in Chinese patients with CLL.