A study of injuries of the deltoid ligament of the ankle in anatomical and clinical material indicates that solitary injury to this ligament is rare; it is more commonly found along with other injuries, including a fracture of the distal part of the fibula. A survey was made of patients treated at the Hitchcock Hospital for major injuries of the deltoid ligament (110 patients in a thirteen-year period). Almost all of these patients were treated by closed reduction and external splinting. In eighty-three patients treated conservatively and with follow-up data available, only eleven had any disability and this was mild. A small number treated by open surgery showed comparable results. On the basis of this study it would seem that the majority of ankles with a complex of injuries including rupture of the deltoid ligament can be treated well by closed reduction and external splinting.