The purpose of this study was to determine if the parachutist ankle brace (PAB) decreases the number and severity of ankle injuries in an airborne Ranger battalion. A retrospective study was performed covering a 38-month period. A computer database was used to track all jump injuries with a diagnosis of ankle pain, sprain, or fracture. The frequency was calculated for ankle injuries per 1,000 jumps and the average length of medically restricted duty per ankle injury. A total of 13,782 static line parachute jumps were conducted during the study period. Without the PAB, 35 ankle injuries were seen (4.5/1,000 jumps), with 9 fractures and 316 days of medical restriction per 1,000 jumps. Using the PAB, 9 ankle injuries were seen (1.5/1,000 jumps), with 3 fractures and 71 days of medical restriction per 1,000 jumps. The correct use of the PAB appeared to significantly decrease the incidence of ankle injuries in this battalion.