Interleukin enhancer-binding factor 3 (ILF3) may function as a transcriptional coactivator and has been reported to be involved in tumor proliferation and metastasis; however, its role and clinical value in gastric cancer (GC) remains unclear. To understand the value of ILF3 in GC, a total of 80 matched samples selected from GC tissues and the adjacent mucosa were used to evaluate the expression of ILF3 and its association with clinical characteristics. Furthermore, its biological functions and mechanisms were investigated using SGC-7901 and BGC823 cell lines. Immunohistochemistry demonstrated that the positive expression rates of ILF3 in GC tissue were higher compared with those in adjacent mucosa (P<0.05). Significantly overexpressed ILF3 was detected in BGC823 and SGC7901 cells, and the MTT results demonstrated decreased cell activity after ILF3 expression was inhibited. The proportions of cells in the G0/G1 phase increased, while the number of cells in the G2/M phase decreased, and the expression of the genes associated with proliferation varied following inhibition of ILF3 (P<0.05). Positive expression of ILF3 was associated with a poor prognosis for patients with GC, and was an independent risk factor for GC (P<0.05). In conclusion, ILF3 is involved in the deterioration of GC by promoting proliferation of GC cells, and ILF3 protein detection may assist in the prediction of the prognosis of patients with GC.