Objective: To investigate the proliferation capabilities, immunophenotype changes, level of secreted cytokines and activities against lymphoma cells under the condition that cytokine-induced killer (CIK) cells co-cultured with dendritic cells (DC) in vitro. Methods: DC and CIK cells were induced from peripheral blood mononuclear cells of healthy volunteers. They were co-cultured meanwhile CIK cells were cultured alone as controls. Increased number of cells were counted by tapan-blue staining, killing activities were detected by MTT assay, immunophenotype changes were analyzed by flow cytometry, the IL-12 and INF-γ levels of the cultured supernatants were detected by ELISA kits. Results: The proliferation capabilities of DC-CIK cells were significantly higher than that of CIK cells (P < 0.05). Under the same condition, the ratio of double positive cells such as CD3+ CD8+, CD3+ CD56+ in CIK cells was significantly enhanced by co-cultured with DC cells (P < 0.05). The level of IL-12 and INF-γ secreted in supernatants was increased noticeably by co-cultured DC-CIK cells on day 3 compared to CIK cells which were cultured alone (P < 0.01 and P < 0.05). Within the effector-target ratio range between 5:1 to 40:1, the activi-ties against lymphoma cells of DC-CIK cells were much higher than that of CIK cells (P < 0.05), and this effect was showed a positive correlation with the effector-target ratio. Conclusion: The proliferation capabilities, the level of secreted cytokines and the activities against lymphoma cells of DC-CIK cells were significantly higher than those of CIK cells. The research might provides theoretical and experimental basis for clinical immunotherapy of DC-CIK cells. Objective: To investigate the proliferation capabilities, immunophenotype changes, level of secreted cytokines and activities against lymphoma cells under the condition that cytokine-induced killer (CIK) cells co-cultured with dendritic cells (DC) in vitro. Methods: DC and CIK cells were induced from peripheral blood mononuclear cells of healthy volunteers. They were co-cultured meanwhile CIK cells were cultured alone as as controls. Increased number of cells were counted by tapan-blue staining, killing activities were detected by MTT assay, immunophenotype changes were analyzed by Flow cytometry, the IL-12 and INF-γ levels of the cultured supernatants were detected by ELISA kits. Results: The proliferation capabilities of DC-CIK cells were significantly higher than that of CIK cells (P <0.05). Under the same condition , the ratio of double positive cells such as CD3 + CD8 +, CD3 + CD56 + in CIK cells was significantly enhanced by co-cultured with DC cells (P <0.05). The level of IL-12 and INF-γ secreted in supernatants was increased noticeably by co-cultured DC-CIK cells on day 3 compared to CIK cells which were cultured alone (P <0.01 and P <0.05). Within the effector-target ratio range between 5: 1 to 40: 1, the activi-ties against lymphoma cells of DC-CIK cells were much higher than that of CIK cells (P <0.05), and this effect was showed a positive correlation with the effector-target ratio. , the level of secreted cytokines and the activities against lymphoma cells of DC-CIK cells were significantly higher than those of CIK cells. The research might provide theoretical and experimental basis for clinical immunotherapy of DC-CIK cells.