OBJECTIVE Traditionally, peripheral nerve lesions are diagnosed on the basis of clinical history, physical examination, and electrophysiological studies, and the role of imaging studies has been limited. The purpose of the study was to assess the usefulness of sonography in diagnosing peripheral nerve lesions. METHODS Thirty adult patients with peripheral nerve lesion/s and 30 healthy adult volunteers were included in the study, and sonography of the relevant peripheral nerve/s was done. The mean cross-sectional area (CSA) of the involved nerves were compared using Student t-test. RESULTS The study included patients with diabetic peripheral neuropathy (DPN), carpal tunnel syndrome, leprosy, peripheral nerve tumor, and peripheral nerve trauma. There was a significant increase in CSA of the median nerve and ulnar nerve in DPN patients, and of the median nerve within the carpal tunnel in carpal tunnel syndrome (P < 0.0001) as compared to age and sex-matched controls. Sonography showed significant thickening of both the ulnar and median nerves in patients with leprosy. On sonography, schwannoma and neurofibroma had a similar appearance and showed internal vascularity. In case of neural trauma, sonography allowed precise localization of the site and type of nerve injury. CONCLUSIONS High-resolution sonography is useful in characterizing peripheral nerve lesions and can complement other diagnostic investigations such as the nerve conduction study. It is easily available and has the potential to become the first modality for the evaluation of focal peripheral nerve disorders.