Introduction: The aim of the study was to systematically analyze the influence of extracorporeal photopheresis (ECP) on the quality of life (LQ) and the course of the disease in patients with Mycosis Fungoides (MF), as well as with Graft-versus-Host Disease (GvHD).Methods: LQ was monitored retrospectively by using the dermatology life quality index (DLQI) and Skindex-29 test before ECP onset and after the last ECP. Disease parameters were assessed by objective criteria i.e. number of associated medical drugs taken, intervals between therapeutic cycles, gradual change of the disease, and eventual side-effects and complications of ECP therapy.Results: Fifty-one patients were treated with ECP during 2008-19; 19 out of 51 died, and follow-up was not completed in 13 patients. Finally, treatment protocols of 671 ECP procedures were evaluated in 19 patients (10 MF; 9 GvHD). MF and GvHD subpopulations did not differ in the individual scores of LQ questions, either before the outset or after the last ECP. DLQI and Skindex-29 scores were ameliorated by the ECP therapy (p= 0.001 and p< 0.001, respectively) due to improvement of individual scores of feelings, daily/social activities (p< 0.05), and functionality (p≤ 0.05). The median interval between ECP cycles was extended from two to eight weeks (p= 0.001). Needs of GvHD patients for drugs being received for the underlying disease were reduced (p= 0.035). Two of the 10 MF patients worsened from stage IIA to IIIA. Severe or minor side effects leading to a therapy interruption were not recorded.Conclusion: Patients with GvHD experienced a notable decrease in the administration of drugs for their underlying condition, and there were no instances of severe side effects that resulted in the discontinuation of treatment. ECP is safe and effective for the treatment of MF and GvHD.