Abstract:Background:The purpose of this study was to determine the epidemiology and history of knee injury and its impact on activity limitation among football premier league professional referees in Iran.Methods:This was a descriptive study. 59 Football Premier League professional referees participated in the study. The knee injury related information such as injury history and mechanism was recorded. Injury related symptoms and their impacts on the activity limitation, ability to perform activities of daily living as well participation in sports and recreational activities was obtained through the Knee Outcome Survey (KOS).Results:The results indicated that 31 out of 59 participants reported the history of knee injury. In addition, 18.6%, 22.4% and 81% of the referees reported that they had been injured during the last 6 months of the last year, and at some point in their refereeing careers, respectively. Results further indicated that 48.8% of the injuries occurred in the non-dominant leg and they occurred more frequently during training sessions (52%). Furthermore, the value of KOS was 85 ± 13 for Activities of Daily Living subscale and 90 ± 9 for Sports and Recreational Activities subscale of the KOS.Conclusions:Knee injury was quite common among the Football Premier League professional referees. It was also indicated that the injuries occurred mainly due to insufficient physical fitness. Therefore, it is suggested that football referees undergo the proper warm-up program to avoid knee injury.