Background: Mycosis fungoides (MF) is the most common cutaneous T cell lymphomas (CTCL). Discrepancies between clinical and histopathological response to MF therapy led to search for more objectively tools to determine the presence of residual/recurrent skin involvement. Therefore, Cluster of Differentiation 163 (CD163) could be an interesting prognostic tool in evaluation of MF therapy. Objective: To evaluate the relationship between serum CD163 level and staging of early MF and its prognostic value in treatment of early MF. Patients and methods: This study was carried out at Dermatology Department, Al-Hussein University Hospital, Faculty of Medicine, Al-Azhar University, during the period from January 2016 to May 2018.      This study included 41 individuals (22 diagnosed as early MF and 19 healthy volunteers). Detection of sCD 163 by ELISA was done in MF patients twice. The first was done before starting treatment and the second was done 6 months after continuous therapy. Detection of sCD 163 of healthy volunteers was done. Results: sCD 163 was significantly higher in MF patients than control group. It significantly reduced after treatment in MF patients, and it reduced significantly in patients received PUVA more than NB-UVB. Conclusion: sCD 163 was elevated in MF patients and a useful follow up marker in early MF.