Hirayama Disease (HD) is a benign lower motor neuron disorder in the young with male preponderance. It is characterized by insidious onset and progressive weakness and wasting of a distal extremity . Generally, this disease is considered a 'benign' and non-progressive motor neuron disease, which stabilizes within five years of onset.We describe a 23-year-old famele patient who experienced progressive amyotrophy with no sensorial abnormality.©2008, Firat University, Medical Faculty.