Preptin is a 34 amino acid peptide that plays a role in glucose homeostasis. The aim of this study was to determine the effect of high intensity training on serum levels of preptin, insulin and glucose in obese adolescents. Twenty-four male students with an average age of 13.43±0.77 years, weight 85.84±8.46 and BMI above 95th percentile were randomly assigned to two groups of exercise and control. The program of the training group was carried out with an intensity of 60-75% of the reserve heart rate as 4 sessions per week for 10 weeks. The measurements were done fasting, before and after the intervention. The data were analyzed using independent and dependent t-test at a significance level of p≤0.05 and using spss20 software. The findings showed that serum levels of preptin (p=0.001), weight (p=0.001) and body fat percentage (p=0.026) in the training group decreased significantly, but insulin (0/370) and glucose (0/238) changes were not significant. There is a significant correlation between preptin changes with changes in weight and body fat percentage (p<0.05). It seems that high-intensity training is associated with a decrease in serum levels of preptin and a decrease in body weight and percentage.