The purpose of this study was to compare the effect of eight weeks of resistance training and irisin injection on BDNF and spatial memory in male rats. 19 male mice (mean weight 18g and 5 weeks old) were randomly divided into control groups, sham, resistance training and irisin injection gruops. The resistance training program was conducted for eight weeks and three days each week. At the first week, the closed weights were 50% of the body weight of the rats and gradually increased to about 200% of their weight in the final week each session consisted of 3 repetitve 5 repetitions with 3 minutes of rest between turns and one minute between repetitions. Irisin injection was also performed three times a week. Elisa method was used to measure plasma irisin and BDNF and to evaluate spatial memory of Barns maze. Results showed a positive and significant correlation between irisin and BDNF (P = 0.66, P = 0.01). Also results showed irisin levels increased significantly in the training groups and irisin injection compared to the control group (P=0.001, F=14.25). This level was higher in the resistance training group than the irisin injection group, but the spatial memory (P=0.658, F=0.546) and BDNF levels (P=0.635, F=0.584) in the two groups did not have a significant effect. It can be concluded 8 weeks of resistance training and irisin injection did not have a significant effect on blood BDNF and spatial memory, but significantly increased the level of irisin
