Mycosis fungoides and Sèzary syndrome are the most studied subtypes common cutaneous T-cell lymphomas. The current treatment objective is to improve the clinical manifestations of the disease in the affected areas, to relieve symptoms and to halt disease progression. Patients with early-stage mycosis fungoides are usually managed with skin-directed therapies, whereas patients with resistant or advanced-stage mycosis fungoides or Sèzary syndrome often require systemic drugs. Over the last decade, new drugs have been developed, increasing the breadth of treatment options for cutaneous T-cell lymphomas patients. Mogamulizumab is a first-in-class defucosylated humanized IgG1 κ monoclonal antibody, which exerts its anti-tumour action by selectively binding to C-C chemokine receptor 4 and increasing antibody-dependent cellular cytotoxicity activity against malignant T-cells. Several clinical trials showed that mogamulizumab is able to effectively control the cutaneous T-cell lymphomas in each site (skin, blood, lymph nodes and viscera), improving patients' symptoms, function and overall quality of life with a manageable safety profile. In this report, we discuss 12 cases of patients with mycosis fungoides or Sèzary syndrome successfully treated with mogamulizumab in real-life clinical practice in Italy.