Carpal tunnel syndrome (CTS) is a common peripheral neuropathy, caused by compression of the median nerve. Symptoms usually are present for months and aggravate over time. Acute onset of complaints and symptoms, like coldness of the hand, should raise awareness of a possible vascular cause of CTS.Persistent median artery (PMA) is a very rare anatomical variant of the blood supply of the upper limb. The presence of a thrombosed PMA is an extremely rare cause of CTS. In this article a case is presented in which the patient has carpal tunnel syndrome of his left hand, caused by a thrombosed persistent median artery. Conservative treatment, consisting of rest, ice application and non-steroidal anti-inflammatory drugs, failed. Surgical excision of the thrombosis and open exploration of the carpal tunnel was performed, with complete relief of symptoms. In literature different treatment options, like conservative treatment with antiplatelet therapy or surgical excision of the throm- bosis and decompression of the nerve, are described with good results. However up until now, no consensus exists about the golden standard in treatment of a thrombosed persistent median artery.