Injury to the lateral ligaments of the ankle joint is one of commonest injuries seen in the casualty department. The diagnostic routines and treatment vary considerably from one hospital to another. The methods for precise diagnosis and treatment are reviewed and discussed and the main emphasis is placed on major prospective investigations. The authors suggest that the diagnosis should be made on the basis of the clinical examination and that, regardless of the degree of ligamental injury, treatment should consist of adhesive strapping. Primary identification of patients with prolonged symptoms is an unsolved problem since the degree of ligamental injury is not a reliable predictor.