Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and a frequent cause of sick leaves because of work-related hand overload. That is why an early diagnosis and adequate treatment (conservative or surgical) are essential for optimal patient management. Aim: The aim of the study is to assess the usefulness of high-frequency ultrasound in CTS for the assessment of patient eligibility for surgical treatment. Material and methods: The study involved 62 patients (50 women and 12 men, aged 28–70, mean age 55.2) with scheduled surgeries of CTS on the basis of clinical symptoms, physical examination performed by a neurosurgeon and a positive result of EMG testing. The ultrasound examinations of the wrist were performed in all these patients. On the basis of the collected data, the author has performed multiple analyses to confirm the usefulness of ultrasound imaging in assessing patient eligibility for surgical treatment of CTS. Results: US examinations showed evidence of median nerve compression at the level of the carpal tunnel in all of the examined patients. This was further confirmed during surgical procedures. The mean value of the cross-sectional area at the proximal part of the pisiform bone was 17.45 mm² (min. 12 mm², max. 31 mm²). Nerve hypoechogenicity proximal to the nerve compression site was visible in all 62 patients (100%). Increased nerve vascularity on the transverse section was present in 50 patients (80.65%). Conclusions: Ultrasonography with the use of high-frequency transducers is a valuable diagnostic tool both for assessing patient eligibility for surgical treatment of CTS, and in postoperative assessment of the treatment efficacy.