Objective: This study aimed to investigate the effect of working memory (WM) training on WM capacity and performance of novice karate practitioners (karateka).Methods: Research method is quasi-experimental with a pretest posttest control group design.A total of 24 karate practitioners were selected among Alborz (Alborz Province, iran) novice karateka by convenience sampling method and were randomly assigned into control and experimental groups. They were asked to complete WM capacity test and performance test.Then, the experimental group underwent a 25 session WM training course. Finally, both group completed the tests again. Instruments of gathering data included digit and spatial WM test, performance test, and WM training software. We used 1-way analysis of covariance (ANCOVA) for data analysis.Results: Our findings showed that WM training resulted in increase in WM capacity (F=61.87, P£0.01) and performance (F=15.5, P£0.01) of the intervention group.Conclusion: We suggest that coaches ask athletes to use WM training as a complement to physical exercises.