Chemotherapy and radiation therapy provide limited improvement in survival of gastric cancer patients after tumor resection. It is essential to develop a novel therapeutics for gastric cancer. In the recent years, cytokine-induced killer cells (CIKs)-based adoptive immune therapy has been explored in gastric cancer patients. Due to the small number of patients included in each clinical trial and low-power statistical analysis, the effectiveness of this approach is still unclear. To address this issue, we systemically analyzed the relevant clinical trial data published in recent years by powerful statistical meta-analysis. Clinical data was searched by multiple electronic databases with a term "gastric cancer" and "cytokine-induced killer cells". Six relevant clinical trials with case-control studies were extracted for our meta-analysis, including 318 patients receiving CIK cell therapy and 369 patients receiving conventional therapy. Overall survival (OS) and odds ratio (OR) were analyzed for patients at 1, 2, 3, and 5 years post-CIK cell therapy and post-conventional therapy. Heterogeneity and publication bias were analyzed for included data quality and publication bias. Our meta-analysis from 6 clinical trials suggests that CIK cell therapy significantly increased 5-year OS from 27±2.44% to 49±7.62% (p<0.05) and 5-year OR up to 1.77 (p<0.05). The increased 5-year survival rate was also highly correlated with the increased CD3+ T cell number and ratio of CD4+/CD8+ in the CIK treated patients. CIK cell therapy significantly increased 5-year survival rate compared to conventional chemotherapy among gastric cancer patients. The study provides powerful statistical evidence for large-scale clinical trials with CIK cell therapy.