Background aims. Despite the availability of multiple treatment strategies, patients with gastric carcinoma (GC) have a dismal prognosis. The aim of this study was to evaluate the efficacy and safety of cellular immunotherapy (CIT) with the use of autologous natural killer cells, gamma delta T cells and cytokine-induced killer cells in combination with chemotherapy in patients with GC. Methods. In this open-label pilot cohort study, patients were treated with the combination therapy (chemo/CIT group) or chemotherapy alone (control group). Progression-free survival (PFS), overall survival (OS), quality of life (QOL) and adverse events were investigated. Results. Fifty-eight patients were analyzed, 30 in the chemo/CIT group and 28 in the control group. The median PFS of the chemo/CIT group was significantly longer compared with the control group (P = 0.021). In subgroup analysis, in patients with stage III GC, node-positive metastasis or poorly differentiated carcinoma, the 2-year PFS rate in chemo/CIT versus control groups was 62.5% versus 26.7% (P = 0.022), 50% versus 27.3% (P = 0.016) and 56.3% versus 28.6% (P= 0.005), respectively. The median OS in either group has not yet been reached, and there was no significant difference in OS between the groups. The QOL was improved in the patients treated with chemo/CIT compared with the control group. CIT was well tolerated and not related to any significant adverse events. Conclusions. A combination of CIT and chemotherapy for patients with GC was safe, improved QOL, and might prevent recurrence, especially in GC patients with advanced stage, poorly differentiated carcinoma or lymph node metastasis.