Background/aim: Peroneal neuropathy at the fibular head (PNFH) is one of the most common entrapment neuropathies. Our aim inthis study was to analyze the efficiency of ultrasonography in the diagnosis of PNFH.Materials and methods: The study included 15 peroneal nerves of 12 patients with PNFH and 24 peroneal nerves of 12 healthy controls.PNFH confirmation was based on clinical and electrophysiological findings. All patients and controls underwent ultrasonographicevaluations for peroneal nerves. The cross-sectional area (CSA) was measured. Echogenicity of the nerve was evaluated by comparing itwith the adjacent connective tissue deep under the subcutaneous fat.Results: CSA measurement of the peroneal nerve is a valuable diagnostic tool in predicting PNFH (AUC: 0.87, 95% CI: 0.73–1.00, P< 0.01). The CSA cutoff value for diagnosing PNFH was found to be 0.115 cm2 with 80% sensitivity and 99% specificity. Hypoechoicperoneal nerve in patients with PNFH was very frequent.Conclusion: Ultrasonography is a useful technique in diagnosing PNFH. In addition to clinic and electrophysiological findings, it mayimprove diagnostic performance.