PURPOSE: The current study aimed to investigate the effects of legumes inclusion in the hypocaloric dietary approaches to stop hypertension (DASH) diet on fasting plasma glucose (FPG) and cardiometabolic risk factors in overweight and obese patients with type 2 diabetes over 16 weeks. Also, the modulatory effects of rs7903146 variant in the transcription factor 7 like 2 (TCF7L2) gene that is associated with the risk of diabetes, were assessed on these cardiometabolic risk factors. METHODS: This study was a randomized controlled trial. Three-hundred participants, aged 30-65 years, whose TCF7L2 rs7903146 genotype was determined, were studied. The participants were randomly assigned to receive either the hypocaloric DASH diet or a hypocaloric legume-based DASH diet. The primary outcome was the difference in FPG change from baseline until the 16-week follow-up between the two dietary interventions. The secondary outcomes were differences in insulin resistance and lipid profile changes between the dietary intervention diets. RESULTS: A reduction in FPG, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), triglyceride, total cholesterol, and low-density lipoprotein cholesterol (LDL-C) was observed at week 16 in both hypocaloric dietary interventions. Compared to the DASH diet, the legume-based DASH diet decreased the FPG and HOMA-IR. There is no interaction between rs7903146 and intervention diets on glycemic parameters. CONCLUSION: The DASH diet, enrich in legumes, could improve the glycemic parameters in participants with type 2 diabetes, regardless of having rs7903146 risk or non-risk allele. REGISTRATION NUMBER OF CLINICAL TRIAL: Iranian Registry of Clinical Trials (IRCT) (code: IRCT20090203001640N17).