Primary cutaneous lymphomas (PCL) are rare skin tumors of lymphoproliferative neoplasms and belong to the heterogeneous group of non-Hodgkin's lymphomas. PCL encompass a broad spectrum of clinical and histologic manifestations, with cutaneous T-cell lymphoma (CTCL) being the most common (73%). Due to the rarity of the diseases, population-based studies of care and epidemiology are limited. Based on anonymized, age- and sex-adjusted SHI (statutory health insurance) claims data of approximately five million SHI-insured patients, a retrospective analysis was conducted over a six-year period (2012-2017) to determine the prevalence, incidence, and lethality in patients with mature-cell T/NK-cell lymphoma in Germany. A total of 1,336 patients with T-cell lymphoma were identified during the observation period. The six-year prevalence ranged from 27.35 to 43.58 per 100,000. Patients were 65% male with a mean age of 66 years (SD 15). There were 246 patients (approx. 20%) who died within the 6years, up to 7% per year. The calculated incidence in 153 identified patients in 2017 is 3.65 to 3.92 per 100,000. For the first time, valid epidemiologic findings of patients with mature T-cell and NK-cell lymphomas were obtained using SHI claims data in Germany. Further analyses are needed to gain a deeper insight into the healthcare reality of patients with this rare disease.