Purpose: We studied the diagnostic value of ultrasonography to confirm the presence of the syndesmosis injuries in the ankle. Materials and Methods: Pre-operative ultrasonography were taken in 42 cases of ankle fractures to determine injury of syndesmosis between February 2000 and August 2003. Tear of syndesmosis was confirmed when they met the following criteria; widening of distal tibiofibular clear space greater than 7 mm on pre-operative AP X-rays, leakage of contrast dye during intra-operative arthrography, and operative findings revealing syndesmosis rupture. We compared these diagnoses with those made by pre-operative ultrasonography. Results: Syndesmosis injuries were confirmed in 23 cases among the total 42 cases. Ultrasonography revealed syndesmosis tear in 25 cases, with 20 cases corresponding with confirmed tear and 5 cases without tear in confirm. Syndesmoses were found to be intact in 17 cases of ultrasonograph, but 3 cases were actually confirmed tear. In ankle ultrasonography, the sensitivity was 90.9%, the specificity was 75.0%. Conclusion: Preoperative ultrasonography is a non-invasive and useful study to determine the syndesmosis injury in ankle fractures.