Introduction: The aim of this study was to investigate the effect of gallic acid on hippocampal level of brain derivative neurotrophic factor (BDNF) in trimethyltin chloride (TMT)- intoxication rats after eight weeks of endurance training. Materials and Methods: Seventy Sprague-dawley male rats were selected and randomly divided into seven groups, including: (1) Control, (2) Sham, (3) Gallic acid 50, (4) Gallic acid 100, (5) Endurance training (4), (6) Training + Gallic acid 50, and (7) Training + Gallic acid 100. Hippocampal degeneration was induced by TMT (8 mg/kg) in all groups except control animals. During eight weeks, rats of groups 3, 6 and 7 ran on treadmill’s without incline at a speed of 15 to 20 meters per minute for 15 to 30 minutes per session, five times weekly. In addition, groups 4 and 6 were treated with gallic acid (50 mg/kg) and groups 5 and 7 with gallic acid (100 mg/kg) every day for 14 days. Results: The findings showed that hippocampal levels of BDNF in all test groups was significantly higher than sham group. Conclusion: Endurance training and gallic acid as well as the combination of them increase the level of hippocampal BDNF in a model of TMT-intoxication.