We examined the effect of trunk exercise for prevention of low back pain on trunk back muscle endurance of elderly people. [Subjects] Twenty-four people (74  5.1 years old) participated in this study. They were assigned to an exercise group or a control group. [Methods] The endurance parameters included the holding time of the Trunk Holding Test (THT) and electromyographic fatigability (IMF, MF-Slope) was also evaluated. [Results] Although a significant change in electromyographic fatigability was not observed after eight weeks of exercise in either group, THT increased significantly only in the exercise group. [Conclusion] The results suggest that the exercises conducted in this study were effective for improvement of THT that is one of the risk factors for low back pain.