BACKGROUND: Advanced non-small cell lung cancer (NSCLC) has remained challenging to treat effectively. This study aimed to investigate the clinical effects and safety of immunotherapy with dendritic cells and cytokine-induced killer cells (DC-CIK) administered with chemotherapy (CT) in this malignancy. METHODS: We have developed a new clinical trial design termed as the prospective patient's preference-based study (PPPS). Consecutive patients (n = 135) with advanced NSCLC were treated with DC-CIK administered with CT or mono-therapy (CT or DC-CIK alone). RESULTS: For all the patients, the median PFS was 5.7 months and the median OS was 17.5 months. The 1-year PFS and OS rates were 29.4% and 58.2%, respectively. The 1-year PFS and OS rates for DC-CIK plus CT were significantly higher than that in the group of patients who received DC-CIK alone and CT alone (P < 0.05). The number of adoptively infused DC-CIK cells was associated with clinical efficacy. After adjusting for competing risk factors, DC-CIK combined with CT and infused number of CIKs remained independent predictors of PFS and OS. Phenotypic analysis of peripheral blood mononuclear cells showed that CD8+CD28+, and CD8+CD28- T cells, changed significantly in all groups (P < 0.01). The CD3+ T cells increased in the chemotherapy plus immunotherapy and the immunotherapy alone group (P < 0.01), while CD3-CD16+CD56 T cells decreased in the chemotherapy plus immunotherapy and the immunotherapy alone group (P < 0.01). CONCLUSIONS: DC-CIK combined with chemotherapy administration resulted in numerically superior PFS and OS compared with monotherapy in advanced NSCLC.