Lipofibromatous hamartoma (LFH) is an extremely rare benign tumor, which is characterized by an excessive infiltration of the epineurium and perineurium by fibroadipose tissues.A 27-year-old woman was diagnosed with left carpal tunnel syndrome (CTS) due to (LFH) of the median nerve. LFH was diagnosed by MRI and sonography; the characteristic ultrasonographic feature of LFH showed a good correlation with pathognomonic MRI findings. The median nerve was involved along its course in the forearm; however, the patient needed carpal tunnel release because of severe compression of the median nerve under the flexor retinaculum.Radiologic evaluation of patient with CTS to evaluate probable secondary CTS is recommended.