As the middle-aged in the society as well as stress-induced cognitive disorders and dementia are increasing, sport is identified as a suitable solution to prevent disorders in central nervous system. The aim of the present study was to compare the effects of 8 weeks of strength and endurance training on BDNF. For this purpose, 150 male wistar rats participated in endurance training (running with 10-25 m/min speed) and strength training (lifting the weight up the special ladder with 104-126% of body weight). Blood samples were collected at the beginning of the protocol, 24 hours after the last session of the 4th week and 24 hours, 3 and 5 days after the last session of the 8th week. Kolmogorov Smirnov test, multifactor analysis of variance and one-way ANOVA were used to compare the means and Pearson correlation coefficient was used to investigate the relationship between BDNF and cortisol. In the 4th and 8th weeks, BDNF increased significantly in strength training group (p=0.014 and p=0.047 respectively) but this increase was not significant in endurance training group (p>0.05). BDNF concentration significantly increased in endurance group compared with control group (p=0.032 and p=0.023 respectively). In the 8th week, three and five days after the last session, cortisol levels increased significantly in endurance group (p=0.046, p=0.02, p=0.044). There was no significant relationship between BDNF and cortisol during sample collection. It seems that intensity and duration of training influence BDNF levels. Moderate intensity training increased BDNF levels but high intensity training inhibited this increase for the reasons such as increased cortisol levels. Also, during training, strength training enhanced BDNF concentrations more than endurance training.