Tension tests or neurodynamic techniques assess the mobility of the peripheral nerves and provide a guide for planning and managing physiotherapy treatments of entrapment syndromes such as carpal tunnel syndrome (CTS). One of the upper limb tension tests (ULTT) is ULTT1 that evaluates the efficacy of physiotherapy treatment. It has been shown to be a valid test but its reliability has not been investigated for CTS. Therefore, it is not known if the ULTT1 helps in diagnosing CTS and assessing CTS treatments. The purpose of this study was to determine the reliability of the ULTT1 in CTS.