Purpose: The purpose of the present research was to translate the original English version of International Knee Documentation Committee (IKDC) Subjective Short Form to Persian and to assess validity and reliability of it in Iranian patients with ACL injury. Method: The Persian version of the IKDC Subjective Short Form was administered to 145 patients including 111 men (76 %) and 34 women (24 %) with the clinical diagnosis of knee ACL tear that were referred to our Knee and Shoulder Center at Mashhad University of Medical Sciences, Mashhad, Iran. The Persian IKDC Subjective Short Form and Persian SF-36 questionnaire were completed by patients in the clinic before beginning any treatment intervention. Patients filled out the Persian IKDC 72 h again before receiving a major treatment; we were then able to use the test–retest method to calculate reliability. Results: The average age of the subjects was 30.9 ± 10.4 years. The calculated ICC with 95 % confidence interval was 0.845. In this study, Cronbach’s alpha was 0.845. There were significant correlations between mean total score of the Persian IKDC and all items of the SF36 (P < 0.05) except for MCS (P = 0.055). Conclusion: Cronbach’s alpha and correlation of IKDC Subjective Short Form and SF-36 demonstrated that the Persian version of IKDC has both strong reliability and validity. The Iranian version of IKDC has favourable validity and reliability and therefore can be used to assess Persian-speaking patients with cruciate ligament injuries. Level of evidence: Level II. © 2014, Springer-Verlag Berlin Heidelberg.