Jian-Hong Chen,1,2,* Po-Hsin Tsai,1,2,* Yin-Chou Lin,2,3 Chih-Ken Chen,1,2 Ching-Yen Chen1,2 1Department of Psychiatry, Chang Gung Memorial Hospital at Keelung, Keelung, Taiwan, Republic of China; 2School of Medicine, Chang Gung University, Taoyuan, Taiwan, Republic of China; 3Department of Rehabilitation, Chang Gung Memorial Hospital at Taoyuan, Taoyuan, Taiwan, Republic of China *These authors contributed equally to this work Objective: To examine the effect of mindfulness-based training on performance and mental health among a group of elite athletes. Methods: This study aimed to evaluate the effect of mindful sport performance enhancement (MSPE) on mental health, flow state, and competitive state anxiety using a 4-week workshop. We recruited an amateur baseball team (N=21) in Taiwan, and collected information by self-reported questionnaires administered before, immediately after, and at a 4-week follow-up. The primary outcome was to evaluate sports performance by flow state and competitive state anxiety, which included self-confidence, somatic anxiety, and cognitive anxiety. The secondary outcome was to explore whether MSPE intervention can improve anxiety, depression, sleep disturbance, and eating disorders.Result: After the workshop and follow-up 1 month later, we found improvements in flow state (P=0.001; P=0.045), cognitive anxiety in competitive anxiety (P=0.056; P=0.008), global eating disorder (P=0.009; P