['The clinical importance of F-wave inversion in the diagnosis of Carpal Tunnel Syndrome (CTS) is not yet well known.', 'This study aims to investigate the value of F-wave inversion in diagnosing CTS, and to evaluate the relationship of F-wave inversion with age, gender, diabetes mellitus, body mass index (BMI), wrist or waist circumferences.', 'Patients (n=744) who were considered to have CTS with clinical findings were included in the study. In order to confirm the diagnosis of CTS, standard electrophysiological parameters were studied with electroneuromyography. In addition, median nerve F-wave measurements were done and we determined if F-wave inversion was present or not. Sensitivity and specificity of F-wave inversion were investigated for its value in showing CTS diagnosed by electrophysiological examination.', 'CTS diagnosis was confirmed by routine electrophysiological parameters in 307 (41.3%) patients. The number of the patients with the presence of F-wave inversion was 243 (32.7%). Sensitivity of F-wave inversion was found as 56% and specificity as 83.8%. BMI and wrist circumference values were significantly higher in patients with F-wave inversion present than those with F-wave inversion absent (p=0.0033, p=0.025 respectively).'] Does value of F-wave inversion in diagnosis of carpal tunnel syndrome and it 's relation with anthropometric measurements?