EN
A quantitative analysis of neoplasma occurring in dogs was performed on the basis of diagnostic pathomorphological examinations. Materials were submitted to the Department of Pathology of the Veterinary Faculty at Warsaw for histopathological examinations and included the biopsies performed during tumor surgeries (819 cases) and tumors found in autopsied dogs (157 cases). A total 976 cases of neoplastic lesions were analysed. The breed of analysed dogs, their age and sex were taken into account. Localization of neoplasms and their biological and histogenetical characteristics were analysed too. More cases of tumors were found in female than in male dogs and they occurred mostly in animals over 5 years of age. Over 50 per cent of neoplastic lesions were localized within the skin, subcutaneously or in the mammary gland. More often epithelial neoplasms were found and the majority of them were malignant.