Objective: To determine the incidence and predictors of early ankle contracture in adults with acquired brain injury. Methods: A prospective cohort study of patients admitted to Neurosurgical Intensive Care Unit (NICU), University Malaya Medical Centre and referred for rehabilitation within a period of 12 months. Adult patients with newly diagnosed acquired brain injury with no prior deformity to lower limbs, Glasgow Coma Scale ≤ 12, no concomitant spinal or lower limb injuries, medical stability at inclusion into the study and agreed to participate for the total duration of assessment (3 months) were recruited. We conducted weekly review of ankle muscle tone and measurement of ankle maximum passive dorsiflexion motion. The end point is reached if ankle contracture developed or completed 3 months post injury assessment. Results: The cohort included 70 patients, of which only 46 patients completed the study. Twenty-eight patients suffered from severe brain injury whilst 18 from moderate brain injury. Out of the 46 patients, 13 (28%) developed ankle contracture at the end of the study period. Abnormal motor pattern was significantly associated with incidence of ankle contracture, which included spasticity (p