BACKGROUND The Danish Veterinary Cancer Registry (DVCR) was established in May 2005 to gather information about neoplasms in the Danish dog and cat populations. Practitioners from more than 60 clinics throughout Denmark have submitted data on these species. The objectives of the current study were, with a special focus on mast cell tumours (MCT) to investigate the occurrence, gender distribution, biological behaviour, locations, types, the diagnostic method used and treatment of skin neoplasms in dogs based on information reported to the DVCR. METHODS From May 15th 2005 through February 29th 2008, reports on a total of 1,768 canine cases of neoplasia in the skin, subcutis or adnexa were submitted.) Of these, 765 cases (43%) were confirmed by cytology or histopathology. RESULTS The majority of dogs had a benign neoplasm (66%) while 21% were cases of malignant neoplasia. The most commonly encountered malignant neoplasms were MCT and soft tissue sarcomas and for benign neoplasms, lipomas and histiocytomas were the most common. The location of the neoplasms were primarily in the cutis, subcutis or in the perianal region. The occurrence, gender distribution, biological behaviour and location of canine skin neoplasias in Denmark were similar to earlier reports, although some national variations occurred. A correlation between grade of MCT and the proportion of cases treated surgically was observed. CONCLUSIONS Population based cancer registries like the DVCR are of importance in the collection of non-selected primary information about occurrence and distribution of neoplasms. The DVCR provides detailed information on cases of skin neoplasms in dogs and may serve as a platform for the study of sub-sets of neoplastic diseases (e.g. MCT) or subgroups of the canine population (e.g. a specific breed).