For years, the relationship between anxiety and performance has been the focus of researchers, and issues related to competitive anxiety have led to reduced athletic performance and failure of athletes in competitions. The aim of this study was to investigate the effect of mindfulness training on competitive anxiety and performance of 13-17 years old female adolescents’ karate. The research is a semi-experimental pretest-posttest design with control group. Thirty-six female karatekas with at least one year of experience who were preparing for the international shotokan competition, were selected. The last kata under their training was evaluated as a pre-test and based on the scores of this test and they were randomly assigned to three groups (experiment with normal post-test, competition and control). The two experimental groups participated in an 8-session course of mindfulness training. In the current research, competitive state anxiety questionnaire-2 and five kata judges (judges) were used. The results of ANOVA test showed that the effect of mindfulness exercises on kata performance and competitive anxiety is significant. Based on the results of performance and anexiety scors, mindfulness exercises probebly are useful in the sport of karate and will improve the performance of female adolescents’ karate.