Angiotensin receptor blockers provide cardiovascular protection in heart failure patients. We have studied the effect of 8 weeks treatment with telmisartan (5 mg kg(-1) day(-1)) on cardiovascular complications associated with streptozotocin (STZ) diabetic rats. Wistar rats were made diabetic with STZ (45 mg kg(-1), iv). Various biochemical and cardiac parameters were measured at the end of 8 weeks. STZ produced hyperglycemia, hypoinsulinemia, hyperlipidemia, increased blood pressure, increased creatinine, cardiac enzyme and C-reactive protein (CRP) levels, reduction in heart rate and cardiac hypertrophy. Chronic treatment with telmisartan significantly (P < 0.05) prevented STZ induced hypertension and elevated fasting glucose level with simultaneous increase in serum insulin levels. It significantly (P < 0.05) reduced the elevated cholesterol, very low density lipoprotein (VLDL) and triglyceride levels in diabetic rats and increased the lower high density lipoprotein (HDL)-cholesterol levels. Further, telmisartan produced a significant (P < 0.05) reduction in the elevated creatinine levels, CRP and levels of other cardiac enzyme markers like Lactate de-hydrogenase and creatinine kinase of diabetic rats. STZ-induced bradycardia was also prevented by telmisartan treatment and it also produced beneficial effect by preventing cardiac hypertrophy as evident from left ventricular collagen levels, cardiac hypertrophy index and left ventricular hypertrophy index of diabetic rats. Our data suggest that telmisartan prevents not only the STZ-induced metabolic abnormalities, but also cardiovascular complications.