This is a randomized controlled trial which assessed the effectiveness of intra-articular hyaluronic acid injection (IAHA) in chronic symptomatic temporomandibular joint (TMJ). Forty four patients with chronic symptomatic TMJ were randomized into 3 groups to receive a series of two injections of either IAHA, saline or conservative treatment. The outcome measures were the pain intensity on visual analogue scale (VAS), maximum mouth opening (MMO), Helkimo clinical dysfunction index (CDI), changes of joint sounds and the quality of life Oral Health Impact Profile questionnaires (OHIP) with 6 months follow up. HA and the saline group had significant improvement of VAS pain scores at rest and MMO ( P < 0.05). The HA and conservative group demonstrated significant improvement of VAS scores during jaw movements ( P < 0.05). All groups had significant improvement of Helkimo CDI and OHIP scores after 6 months ( P < 0.05). Eleven out of 16 patients in the HA group had significant improvement of the joint sounds and there was significant difference between the three groups ( P < 0.05). There was no serious complication in the study. This RCT found that there was no significant difference in most of the outcome measures between patients who were treated either with HA, saline or conservative treatment. The most significant result was the improvement of the joint sounds in the HA group. The current report is an evaluation which shows promising results but a longer term study with a larger sample size is required before any significant differences between the study groups can be ascertained.