This study was performed to investigate the effect of a raw diet (RD) on blood glucose and immune function in non-diabetic (normal) and streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were assigned to four groups (normal control, normal RD, diabetic control and diabetic RD). The control groups and the RD groups were fed an AIN-diet and RD for four weeks, respectively. Weight gain was statistically lower in the RD groups than in the controls. Fasting plasma glucose was significantly lower in the diabetic RD group than in the diabetic control group. The $CD4^+$ T-cell population was higher along with the $CD4^+/CD8^+$ ratio of the mesenteric lymph nodes in the normal RD group compared to the other groups. It can be concluded that RD may reduce the plasma fasting glucose concentration in diabetic rats and improve mesenteric lymph node immune function in normal rats.