Abstract: Objective To investigate the effects of interleukin-24 gene (IL-24) combined with arsenic trioxide (As₂O₃) on kidney cancer cell line Ketr-3. Methods Ketr-3 cells were divided into four groups: a PBS group, a As₂O₃ group (As₂O₃=5 mg/L), a IL-24 group (pCDNA3.1-IL-24=3 μg), and a combination group (3 μg pCDNA3.1-IL-24 + 5 mg/L As₂O₃). After treatment for 48 h, the expression of IL-24 in each group was detected by ELISA. Single cell gel electrophoresis was used to observe DNA fragmentation. Micronucleus experiment was perfomred to detect cellular chromosome fracture. Flow cytometry was used to detect cell apoptosis. Results Compared with the PBS group, the levels of IL-24 in the IL-24 group and the combination group significantly increased (P<0.01). According to single cell gel electrophoresis and micronucleus test, DNA and chromosome damage increased in the combination group, compared with the As₂O₃ group (P<0.05). Flow cytometry assay showed that the apoptosis rate remarkably increased in the As₂O₃ group, the IL-24 group and the combination group, compared with the PBS group (P＜0.05), where the highest apoptotic rate was detected in the combination group (P＜0.05). Conclusions The combined use of IL-24 and As₂O₃ produces synergistic effects and can further stimulate antitumor effects against Ketr-3 cells.