Our previous finding showed that down-regulation of CD3ζ gene was detected in patients with chronic myeloid leukemia (CML). In order to further elucidate the feature of T cell immune status in the signal transduction in CML patients, the expression patterns of all 4 CD3 genes were characterized in peripheral blood of patients, the expression levels of CD3γ, δ, ε and ζ chain genes were detected by real time qPCR with SYBR Green I staining in peripheral blood mononuclear cells (PBMNCs) from 17 cases of de novo CML patients in chronic phase and 17 cases of healthy individuals, the ß₂-microglobulin gene was used as an internal reference, and the mRNA expression level of each CD3 gene was evaluated by the 2(-ΔCt) x 100% method. The results showed that the median expression levels of CD3γ, δ and ε genes (2.344%, 0.515% and 3.516%) in CML patients were not significantly different from healthy individuals (p = 0.072, p = 0.190, p = 0.615, respectively), while the expression level of CD3ζ gene in PBMNCs from CML patients (0.395%) was lower than that from healthy individuals (1.538%) (p < 0.001). The expression patterns of 4 CD3 genes in proper order were CD3ε > CD3γ > CD3δ > CD3ζ in CML group, in contrast, the expression patterns were presented as CD3γ > CD3ε > CD3ζ > CD3δ in healthy group. It is concluded that the present study characterized the expression pattern of CD3γ, δ, ε and ζ chain genes in CML patients, lower expression of CD3ζ is the feature of TCR signal transduction immunodeficiency and the expression patterns of 4 CD3 genes are changed in CML patients.