What are prognostic factors for incomplete recovery, instability, re-sprains and pain intensity 12 months after patients consult primary care practitioners for acute ankle sprains?Observational study.One hundred and two patients who consulted their general practitioner or an emergency department for an acute ankle sprain were included in the study.Possible prognostic factors were assessed at baseline and at 3 months follow-up. Outcome measures assessed at 12 months follow-up were self-reported recovery, instability, re-sprains and pain intensity.At 3 months follow-up, 65% of the participants reported instability and 24% reported one or more re-sprains. At 12 months follow-up, 55% still reported instability and more than 50% regarded themselves not completely recovered. None of the factors measured at baseline could predict the outcome at 12 months follow-up. Additionally, prognostic factors from the physical examination of the non-recovered participants at 3 months could not be identified. However, among the non-recovered participants at 3 months follow-up, re-sprains and self-reported pain at rest at 3 months were related to incomplete recovery at 12 months.A physical examination at 3 months follow-up for the non-recovered ankle sprain patient seems to have no additional value for predicting outcome at 12 months. However, for the non-recovered patients at 3 months follow-up, self-reported pain at rest and re-sprains during the first 3 months of follow-up seem to have a prognostic value for recovery at 12 months.