Background This study compared the effects of a bean-based and a white rice-based breakfast diet on postprandial glucose and insulin levels in Chinese patients with type 2 diabetes mellitus (T2DM). Material/Methods We recruited 63 patients with T2DM. The patients participated in the randomized 2×2 crossover trial. The bean-based diet group and white rice control group were matched for 50 g of available carbohydrate at breakfast. The patients followed the diets for 3 days. Vein blood samples were collected at 0, 30, 60, 120, and 180 min after eating. Data were analyzed using a repeated-measures analysis of variance. The results are expressed as the mean±standard error of mean (SEM) or as the median with interquartile range values. Results Compared with the white rice control, postprandial glucose was significantly lower with the bean-based diet treatments at 60 min ( P =0.004), 120 min ( P =0.000), and 180 min ( P =0.000). The insulin levels of the bean-based diet group were significantly higher at 60 min ( P =0.013). The C-peptide levels of the bean-based diet group were significantly higher at 30 min ( P =0.042) and 60 min ( P =0.005) postprandial. The glucose area under the curve (AUC) showed a similar trend ( P =0.000). There were no statistically significant differences in the AUC of insulin and C-peptide, except C-peptide AUC at 0 to 60 min ( P =0.027). Conclusions Compared with a white rice-based breakfast, a bean-based diet significantly reduced postprandial glucose levels and promoted insulin secretion. These results support a dietary approach to reduce postprandial hyperglycemia.