42 patients with osteoarthrosis with inflammation were included in the study. After randomization and with single-blind technique, they were given intra-articularly in the knee joint either 20 mg of triamcinolonehexacetonide (TH) or 6 mg of the combination betamethasone acetate and betamethasone disodiumphosphate (BM). The patients were studied up to six months after the injection. Initially, week one, two, four and at the time for a possible new injection; pain, local tenderness and joint range were evaluated. At the control in week one, two and four, a general evaluation of effect was also performed. Duration of effect was defined as patient's need of a new injection or other therapy during a six-month period. Results. In the evaluation of effect in local tenderness and pain, TH gave a significant better result already after one week. The improvement in joint range was more pronounced with TH. Also in the general evaluation significantly better results were shown with TH. In general evaluation all patients with TH were considered to improve with two weeks treatment. The duration of effect was significantly longer with TH. After three months five patients in the TH group respectively 12 patients in the BM group needed new therapy. The reported side-effects were not considered to be serious. The investigation has shown that TH gives a pronounced effect and long duration which has resulted in that TH is a preferable drug when long effect is needed in the treatment of osteoarthrosis with concomitant inflammation.