Objective: To investigate the value of high frequency ultrasonography in the diagnosis of zone 2 flexor tendon injuries. Subjects and Methods: Ninety-two patients (49 males and 43 females, mean age 32.6 ± 11.2 years) with zone 2 flexor tendon injuries in one or more digits were randomly divided into a study (n = 46, 95 digits) and a control group (n = 46, 90 digits). In the study group, preoperative ultrasound was performed and surgical repair was conducted based on ultrasonographic findings. Diagnosis and surgical repair of the control group was based on history of trauma and physical examination. Results: Types of ruptures (complete or partial) and the location of the distal end of the ruptured tendon diagnosed by preoperative ultrasonography were consistent with surgical findings in all cases (95/95, 100%) of the study group, whereas the concordance rate between clinically diagnosed ruptures and surgical findings was only 34.4% (31/90) in the control group (p = 0.02). Conclusion: Preoperative high frequency ultrasound examination yielded excellent diagnostic accuracy for zone 2 flexor tendon injuries.