SARS-CoV-2 is a novel coronavirus that, since its appearance in 2019 in Wuhan, China, has spread throughout the world and significantly affected the health of people and animals. In humans, the virus causes a disease called COVID-19, most often characterized by respiratory and digestive symptoms, and in some people with long-term consequences. In addition to humans, the appearance of a certain clinical signs has also been recorded in some animal species. In minks on farms, wild animals from zoos and certain types of pets, infection with the virus and the appearance of clinical symptoms have been proven. In this research, the infection of dogs and cats with the SARS-CoV-2 virus in the territory of the Republic of Croatia was tested. The animals were tested for, Alpha, Delta and Omicron, the three most commonly isolated variants in humans. Neutralizing antibodies were detected from serum samples collected during the admission of animals to the Clinics of the Veterinary Faculty of the University of Zagreb. Serum samples were collected from January to April 2022. 296 dog serum samples and 140 cat serum samples were collected. A prerequisite for the selection of samples was that the animals had complete anamnestic and physical examination data in the medical records. The VN-test showed a seroprevalence of 21.9% in dogs and 18.6% in cats. The animals were tested positive for all three variants and proved that there is an equal possibility of infection with each of the mentioned variants. In contrast to humans, a significant level of crossneutralization was recorded in dogs and cats, which points to a different immune response. It is interesting that age and sex, which have been emphasized as important factors in humans and in the past in animals, did not affect the susceptibility of animals to the virus. Regardless of this, it has been proven that the clinical signs of some animals can be associated with SARSCoV-2 virus infection. Gastrointestinal symptoms are more pronounced in dogs and respiratory symptoms in cats. For a better understanding of the pathogenesis in animals as well as their influence as a source of infection for others, further research into the occurrence of viruse in them is necessary.