Background: Extracorporeal photopheresis (ECP) as a part of multimodality therapy, is one of the treatments for Sézary syndrome (SS) and advanced stage mycosis fungoides (MF). This study aims to describe cutaneous and peripheral blood responses of patients with MF and SS who received multimodality therapy. Methods: In this cross-sectional retrospective study, patients with MF or SS who received ECP treatment in combination with at least one additional systemic treatment between 2011 and 2018 were included. ECP consisted of a two-session cycle every 2 to 4 weeks. Cutaneous and blood responses were evaluated with updated criteria. Results: Twenty-eight patients (11 (39%) with MF and 17 (51%) with SS) were included. Their median age at diagnosis was 63 (57-67) years. The median number of treatments before ECP was 2 (1-3). Seven out of 11 patients with MF (63%) underwent an assessment of cutaneous response. Five patients (70%) presented a partial response; 1 (15%), stable disease, and 1 (15%) progressive disease. Thirteen of the 17 patients with SS (76%) underwent evaluation. One patient (8%) presented a complete cutaneous response; 6 (46%), a partial response; 5 (38%), stable disease; and 1 (8%), progressive disease. None of them relapsed during the study period in both groups. No ECP-related adverse effects occurred during the study. Conclusion: Most patients with SS and MF who underwent multimodality therapy with ECP had favorable cutaneous and blood response. It is safe to combine ECP with other treatments. Studies with large numbers of patients are necessary to assess the effects of ECP on patient survival.