Cat breeding has become very popular nowadays. The presence of these animals in catteries, especially in conditions of imperfect compliance with sanitary and hygienic requirements, often causes outbreaks of viral diseases, the causative agents of which are transmitted mainly by the aerogenic transmission mechanism. Calicivirosis is the most common kennel disease; it can occur as a mono-infection and can also be associated with other viral respiratory diseases. The study aimed to evaluate the epizootic features and clinical course of feline calicivirus in catteries. It was found that the disease's stationary focus was in the experimental cattery. Depending on the year's season, the morbidity increase begins in April, peaks (40 %) in July, and gradually decreases until September. The most vulnerable age group is kittens aged 2–6 months due to imperfect immune mechanisms at this age. The disease occurs mainly manifestly in this age group, with characteristic pronounced clinical signs. Sick cats have sub febrile or pyretic fever, lack of appetite, and salivation with viscous saliva. Ulcers develop on the mucous membranes of the oral cavity. Also, erosions and ulcers are noted in the nasal mirror and on the mucous membrane of the larynx. There was conjunctivitis with serous to catarrhal-purulent exudate. Laboratory tests revealed leukopenia, acceleration of erythrocyte sedimentation rate, left shift of the nucleus, lymphocytosis, and monocytosis, which indirectly determine the viral disease and stimulation of immune functions, and the development of a systemic inflammatory response. Biochemical tests revealed the development of intoxication syndrome, hepatitis liver failure, and renal failure. The data obtained prove the systemic nature of the impact of calicivirus infection, the development of complications in the form of a systemic inflammatory response, which affects various organs and systems, particularly the liver and excretory system. The development of multiorgan pathology in feline calicivirus infection requires an integrated approach to treatment, including pathogenetic and symptomatic measures in the treatment protocol.