We randomized 73 patients with grades II and III ankle sprain to treatment with an Air-Stirrup ankle brace or a compression bandage. All patients were instructed to attempt early motion and weight bearing when comfortable. Ankle function was evaluated after 3-5 days and 2, 4, and 10 weeks with a clinical examination, the Sickness Impact Profile questionnaire, Karlsson's scoring scale and recording of sick leaves. The group treated with the Air-Stirrup ankle brace was more mobile in the initial phase of rehabilitation and had a shorter sick leave. Ankle brace treatment resulted in socioeconomic savings.