Aims: Comparison of the effectiveness of the injection of hyaluronic acid (Ostenil¨) and cortisone (Volon¨) into the facet joints in the treatment of facet joint syndrome. Methods: 60 patients suffering from low back pain due to degenerative arthritis of the facet joints were included in this randomized, controlled, double-blinded, clinical trial. 30 patients received intra-articular injections of hyaluronic acid (Ostenil¨) and 30 patients received intra-articular injections of 10mg triamcinolon-hexacetonid (Volon 10¨). The facet joints of the spinal segments L3/L4, L4/L5, and L5/S1 were injected bilaterally with computed tomography guidance in intervals of one week each. Clinical evaluation was carried out one week prior þrst injection, at the day of þrst injection, after one, two, and three weeks, and after three and six months. Clinical assessment was carried out using the visual analog scale for pain, the Roland Morris Questionnaire, and the Oswestry Disability Questionnaire. Quality of life was assessed using the SF-36 health questionnaire. Radiological assessment was done according to Kellgren. Results: Pain reduction was achieved faster in the Volon 10¨group. After three months the Ostenil¨group reached better pain reduction and this effect lasted for a longer period. The Roland Morris score, the Oswestry Disability Questionaire, as well as the Low Back Pain Outcome Score showed signiþcantly better results in the Ostenil¨group after 3 and 6 months follow-up. Conclusion: Even though no signiþcant difference was found in the short-term follow-up, the results in the Ostenil¨group were comparable to the Volon 10¨group, and were signiþcantly better in the long-term follow up. Thus the intra-articular injection of hyal-uronic acid (Ostenil¨) is an effective alternative in the treatment of low back pain caused by facet joint syndrome, avoiding the known side effects of cortisone.