We assessed the major factors regulating adiponectin levels and the influence of exercise training on adiponectin levels in young obese men (19.2 +/- 1.1 yrs, BMI: 31.1 +/- 4.2, % fat: 27.2 +/- 3.9%). Subjects were separated into three groups ( aerobic exercise group [AE: n=7], aerobic and resistance exercise group [AE + RE: n=7], control group [n= 7]). AE underwent an 8-week training program (three times per week, more than 30 min endurance exercise at ventilatory threshold (VT) intensity). AE + RE went through resistance exercise two or three times per week together with the above endurance exercise for 5 months. Prior to intervention (n=21), adiponectin levels were significantly correlated with percentage of fat. Stepwise multiple regression analysis revealed that percent body fat was an independent predictor of basal adiponectin levels (r(2)=0.370; P < 0.01). After intervention, fat mass, and VT were significantly improved in AE. AE + RE exhibited significant reduction in weight, BMI, percent body fat and fat mass, and had significantly increased VT, VO2 VO2 max; cycling power and torque. Insulin was not changed in both groups. The control group exhibited no significant change in any variables. Although adiponectin levels were unchanged in the three groups, a significant negative correlation between delta fat mass and delta adiponectin levels was observed (n=21, r=- 0.461, P < 0.05). In addition, delta percent body fat was an independent predictor of delta adiponectin levels (r(2)=0.327, P < 0.05). These findings indicate that for increasing the adiponectin level, improvement of the body composition of young obese men is more important than the way training is performed.