Aim: A high prevalence of carpal tunnel syndrome (CTS) in patients with fibromyalgia has been reported and this seems to affect patients’ quality of life. This study aimed to investigate whether there is any relationship between disease activity and quality of life (QoL) in fibromiyalgia patients with CTS and electrophysiological and ultrasonographic measurement values. Material and Method: The cross-sectional study included 102 fibromyalgia patients with CTS symptoms and 102 healthy control subjects. Tender Points Count, Pain Location Inventory, and Symptom Impact Questionnaire were recorded for the FM group. Overall disease impact was assessed with the Fibromyalgia Impact Questionnaire and quality of life with the Nottingham Health Profile. The median nerves of all participants were evaluated electrophysiologically and ultrasonographically. The electrophysiological and ultrasonographic measurements were compared between the groups, then the electrophysiological and ultrasonographic measurements of the fibromyalgia patients were compared with disease activity and QoL. Results: Compared to the control group and the fibromyalgia group with no CTS determined electrophysiologically, the distal median nerve was found to be enlarged in the fibromyalgia group on ultrasonography (p=0.001). The distal median nerve area was determined as a factor with an effect on QoL and disease severity (p=0.037, p=0.041). Conclusion: Fibromyalgia patients with CTS symptoms but electrophysiologically normal results can be evaluated with US. CTS severity affects quality of life and disease severity in fibromyalgia. These results, which have been previously shown electrophysiologically, are now supported by US. Further studies are required to confirm these results.