We report a prospective trial of 66 patients with intraarticular fractures of the calcaneum. All fractures were assessed by CT. Patients with displaced fractures were randomised to receive either conservative (n = 31) or operative treatment (n = 25). Undisplaced fractures (n = 10) were treated conservatively. Operation involved open reduction of the posterior subtalar joint, and fixation with Kirschner wires. All 66 patients were reviewed at a minimum of one year (mean 23 months). After conservative treatment the undisplaced fractures had slightly better results than the displaced fractures. There was no significant difference in outcome between the operatively and the conservatively treated displaced fractures. We have also documented prospectively the natural history of the injury, which is of use in assessing prognosis for both clinical and medicolegal purposes.