Background: This study was designed to see if stability based criteria are useful in choosing between nonoperative and operative treatment of ankle fractures. Materials and Methods: One hundred sixty ankle fractures in skeletally mature patients were retrospectively analyzed to obtain an epidemiological profile in a population of about 130,000. One hundred thirty patients had followup of more than 2 years. A decision between operative and nonoperative treatment was made by the surgeon-on-duty, based on accepted stability criteria. Fractures were classified according to Weber and Lauge-Hansen systems. Clinical outcome was assessed using the scoring systems of Olerud-Molander, the RAND 36-Item Health Survey and the Visual Analogue Scale (VAS), measuring pain and function. Results: The overall incidence of ankle fractures was 154/100,000. Nonoperatively treated patients had more displacement of the distal fibula after treatment, but less pain and better Olerud-Molander (good or excellent, 89% vs. 71%) and VAS functional scores. Independent factors for worse outcome were female gender, older age, unstable fracture and co-morbidity. No nonoperatively treated patients needed operative fixation during followup. Conclusion: Stability-based fracture classification was a simple and useful tool in decision-making for the treatment of ankle fractures. We found lateral malleolar fractures could be treated nonoperatively with success if the ankle mortise was stable. Displacement of the distal fibula after treatment did not affect functional scores or pain. Level of Evidence: III, Comparative Case Series