Aim: Irisin is a recently identified exercise-induced hormone that increases energy expenditure. The effect of chronic aerobic training intensity on irisin concentration is not well known. Thus, we examine the effect of aerobic training intensity on irisin in streptozotocin (STZ) -induced diabetic Wistar rats. Material & Methods: Diabetes was induced by intraperitoneal injection of STZ. Animals were randomly divided into four groups (n=8 in each group): control group (CON), diabetes group (D), diabetes and moderate-intensity exercise group (D + ME; running speed was set at 10-17 m.min-1), and diabetes and high-intensity exercise group (D + HE; running speed was set at 17-28 m.min-1). The rats in the exercise groups were made to run on the treadmill for 30 min per one day, 3 times a week, during 8 weeks. Results: The results indicated that serum irisin concentration was higher in the D + HE group than CON, D and D + ME groups (P<0.05) and no significant differences were observed between CON group and D + ME group. Conclusions: Our findings suggest that that exercise intensity has an effect on exercise-induced irisin responses. Manuscript profile