With this paper we wanted to investigate the occurrence and characteristics of neoplastic changes in Croatian indigenous dog breeds in order to begin building the foundation for further research of this important national and cultural heritage of the Republic of Croatia. Efforts were made to collect as much data as possible on various tumors of indigenous dog breeds from tissue and carcass samples that arrived at the Department of Veterinary Pathology, Faculty of Veterinary Medicine, University of Zagreb, in the period from 2009 to 2019. Looking at each indigenous breed separately, we determined the frequency of tumors, the sex of dogs with neoplastic changes and their average age, the most common localizations where tumors developed, the most common types of these tumors and the biological behavior of each. The analysis of data showed that all breeds had an equal number of male and female dogs and that they were all on average older in age. Also, tumors of malignant biological behavior dominated, likewise most tumors appeared on the skin, mammary gland and hemolymphatic system. Since there is no literature data on neoplastic changes in Croatian indigenous dog breeds, we compared all obtained and comparable results with available data on neoplastic changes in the general dog population and examined their coincidence. In order to obtain more accurate and relevant knowledge about tumors, as the most common pathological changes, it is necessary to conduct further research on a larger number of dogs of indigenous breeds, which would contribute to the preservation of this Croatian national and cultural heritage.