The effects of calcium channel blockers (CCB)-verapamil, nifedipine, diltiazem on metabolic control in streptozotocin-induced long-term diabetes in rats were investigated. Diabetes mellitus was induced by single intravenous injection of streptozotocin (65 mg/kg body wt.). The animals were divided into five groups: a healthy control group, a diabetic group and three diabetic groups treated with one of the calcium channel blockers (verapamil, 25 mg/kg/day, nifedipine, 20 mg/kg/day, and diltiazem, 30 mg/kg/day, respectively). Body weight, glycemia, glycated hemoglobin and total serum protein levels of these animals were measured at the beginning and at the end (after 13 weeks) of the experiment. It was observed that diabetic animals who were not treated with CCB had lost weight at the end of the experiment (P < 0.01). The blood glucose and glycated hemoglobin levels were increased in the diabetic group in comparison to the healthy control group (P < 0.001). However, the calcium channel blockers seem to have beneficial effects on body weight, glycated hemoglobin and blood glucose levels.