Mycosis fungoides is a malignancy of mature helper T cells, generally presents with flat, eczematous patches or infiltrated plaques. The microscopic characteristics of the plaque stage of mycosis fungoides are clear. The polymerase chain reactions (PCR) is an extremely sensitive method for the detection of monoclonal cell population. The aim of this work is to evaluate the PCR as a diagnostic tool in early mycosis fungoides by detecting chain T cell receptor gene rearrangement.