We compared two conservative methods of treating Weber B1 (Lauge-Hansen supination-eversion 2) isolated fractures of the lateral malleolus in 65 patients. Treatment by immediate weight-bearing and mobilisation resulted in earlier rehabilitation than immobilisation for four weeks in a plaster cast. There was no significant difference in the amount of pain experienced or in the requirement for analgesics and early mobilisation was not associated with any complications. We therefore advocate early mobilisation for these stable ankle fractures.