Lisbet Rosenkrantz Hölmich,1 Siri Klausen,2 Eva Spaun,3 Grethe Schmidt,4 Dorte Gad,5 Inge Marie Svane,6,7 Henrik Schmidt,8 Henrik Frank Lorentzen,9 Else Helene Ibfelt10 1Department of Plastic Surgery, 2Department of Pathology, Herlev-Gentofte Hospital, University of Copenhagen, Herlev, 3Institute of Pathology, Aarhus University Hospital, Aarhus, 4Department of Plastic and Reconstructive Surgery, Breast Surgery and Burns, Rigshospitalet – Glostrup, University of Copenhagen, Copenhagen, 5Department of Plastic Surgery, Odense University Hospital, Odense, 6Center for Cancer Immune Therapy, Department of Hematology, 7Department of Oncology, Herlev-Gentofte Hospital, University of Copenhagen, Herlev, 8Department of Oncology, 9Department of Dermatology, Aarhus University Hospital, Aarhus, 10Registry Support Centre (East) – Epidemiology and Biostatistics, Research Centre for Prevention and Health, Glostrup – Rigshospitalet, University of Copenhagen, Glostrup, Denmark Aim of database: The aim of the database is to monitor and improve the treatment and survival of melanoma patients.Study population: All Danish patients with cutaneous melanoma and in situ melanomas must be registered in the Danish Melanoma Database (DMD). In 2014, 2,525 patients with invasive melanoma and 780 with in situ tumors were registered. The coverage is currently 93% compared with the Danish Pathology Register.Main variables: The main variables include demographic, clinical, and pathological characteristics, including Breslow’s tumor thickness, ± ulceration, mitoses, and tumor–node–metastasis stage. Information about the date of diagnosis, treatment, type of surgery, including safety margins, results of lymphoscintigraphy in patients for whom this was indicated (tumors > T1a), results of sentinel node biopsy, pathological evaluation hereof, and follow-up information, including recurrence, nature, and treatment hereof is registered. In case of death, the cause and date are included. Currently, all data are entered manually; however, data catchment from the existing registries is planned to be included shortly.Descriptive data: The DMD is an old research database, but new as a clinical quality register. The coverage is high, and the performance in the five Danish regions is quite similar due to strong adherence to guidelines provided by the Danish Melanoma Group. The list of monitored indicators is constantly expanding, and annual quality reports are issued. Several important scientific studies are based on DMD data.Conclusion: DMD holds unique detailed information about tumor characteristics, the surgical treatment, and follow-up of Danish melanoma patients. Registration and monitoring is currently expanding to encompass even more clinical parameters to benefit both patient treatment and research. Keywords: melanoma, malignant melanoma, clinical database, quality database, melanoma registry, Denmark