Intra-articular treatment with HA and hylans has recently become more widely accepted in the armamentarium of therapies for OA pain Intra-articular HA treatment for osteoarthritis of the knee was approved by the US Food and Drug Administration in 1997 This study is the 1st study in Egypt that analyze the comparison between intra-articular injection of LMW and HMW hyaluronan in the treatment of osteoarthritis knee which was assessed using WOMAC index and visual analogue scale.