In non-small cell lung carcinoma (NSCLC), the immune system fails to eradicate established tumors partly due to the induction of immune tolerance within the tumor microenvironment. Plasmacytoid dendritic cells (pDCs) play critical roles in regulating the immune system. In this study, we investigated pDCs in the peripheral blood of NSCLC. CD4 + CD123 + BDCA2+ pDCs were tested from peripheral blood mononuclear cells in 52 NSCLC patients and 52 healthy controls by flow cytometry. Results revealed that proportion of pDCs was significantly increased in cases than in controls (0.52 ± 0.07% versus 0.21 ± 0.02%, p < 0.001), whereas myeloid dendritic cells (mDCs) did not present any obvious difference between patients and healthy donors (0.25 ± 0.04 % versus 0.18 ± 0.02%, p = 0.120). We further studied pDCs in NSCLC patients with different clinical stages. Data showed that cases with higher stages (III/IV) had elevated level of pDCs than those with lower stages (I/II) (0.65 ± 0.09% versus 0.25 ± 0.07%, p = 0.006). In addition, the amount of pDCs was identified to be associated with squamous cell carcinoma, one of the major subtypes of NSCLC. Interestingly, we observed that smoking patients presented significantly elevated pDCs than those non-smokers (0.63 ± 0.09% versus 0.22 ± 0.05%, p = 0.008). These data suggested that pDCs may be closely involved in the pathogenesis of NSCLC and may predict the progression of the disease.