PurposeTo validate and assess the cross‐sectional adaptation of the modified Cincinnati knee rating system (MCRKS) Persian translation.MethodsTo assess test‐pretest reliability, 102 participants were asked to fill out the MCRKS (Per) scale after anterior cruciate ligament (ACL) reconstruction surgery. Internal consistency (Cronbach's α), reliability (intraclass correlation coefficients), construct validity (Pearson's r) and sensitivity (floor/ceiling effect) were determined. In addition, patients completed other relevant measures as the ACL return to sports after injury (ACL‐RSI) survey, hospital for special surgery ACL satisfaction survey (HSS ACL‐SS), visual analogue scale (VAS) of pain and patient's satisfaction, Tegner activity score (TAS), single assessment numeric evaluation, and Lysholm score.ResultsUsing MCRKS (Per), the internal consistency (Cronbach's α) was 0.9 (if item deleted: 0.81–0.86); the construct validity (Pearson's r) varied between –0.50 (for VAS pain scale) and 0.79 (for Lysholm score); the reliability (ICC value) varied between 0.82 and 0.97; furthermore, no ceiling or floor effect was present.ConclusionThe MCRKS (Per) has adequate measurement properties and is considered a valid, reliable and sensitive instrument which can identify clinical outcomes after ACLR surgery.Level of EvidenceLevel IV.