We performed a crossover study in hypertensive patients with type 2 diabetes to compare olmesartan (40 mg/day) with telmisartan (80 mg/day) in terms of their antihypertensive and metabolic effects. The subjects were 36 patients (20 men and 16 women) with type 2 diabetes who did not achieve a blood pressure <130/80 mmHg following treatment with olmesartan at 40 mg/day or telmisartan at 80 mg/day for 8 weeks or more. The primary endpoint was the blood pressure reduction rate, while the secondary endpoints were BMI, parameters of glucose metabolism, HMW-adiponectin, hs-CRP and lipids metabolism. All parameters were measured in Weeks 0, 12, and 24. Treatments were switched in Week 0, and Week 12 and the following results were obtained. There were 1) no significant differences in baseline characteristics; 2) no significant difference of the blood pressure reduction rate; 3) significant reductions of HbA1c (NGSP), FPG and HOMA-IR in olmesartan group; 4) a significant increase of HDL-C in olmesartan group; 5) a decrease of hs-CRP and a increase of HMW-adiponectin in olmesartan group; and 6) a positive correlation between the percent changes of HOMA-IR and hs-CRP in olmesartan group. In conclusion, there was no difference of the blood pressure reduction achieved at the highest dose in olmesartan group and telmisartan group. But improvement of glycemic control and insulin resistance was only observed in olmesartan group. Because there was a correlation between the percent changes of HOMA-IR and hs-CRP, these effects of olmesartan might be mediated by an anti-inflammatory action.