Coronaviruses (Coronaviruses; CoV) are among the important pathogens that threaten human and animal health. In humans, prominent diseases due to these viruses are severe acute respiratory syndrome (SARS), Middle East Respiratory syndrome (MERS) and SARS CoV-2 (Covid-19), which causes pandemics all over the world today. Feline infectious peritonitis (FIP) is a fatal disease in domestic and wild cats caused by coronaviruses (FCoVs). FCoVs; There are 2 biological types known as feline infectious peritonitis virus (FIPV) and feline enteric coronavirus (FECV). Although 90% of cat populations have antibodies against FCoVs, FIP develops in only 5-10% of cats infected with FCoV. There are two theories about the pathogenesis of FIP. The first of theory is the hypothesis that virulent and avirulent FCoV strains coexist in cat populations, and the second is the "in vivo mutation hypothesis". According to this hypothesis, In cats infected with apatogenic FCoV, the virus genome is spontaneously mutated. As a result of mutation, the virus gains the ability to replicate continuously in macrophages and this situation plays a key role in the pathogenesis of FIP. Clinically, antemortem diagnosis of FIP is still difficult. In cases without effusion, definitive diagnosis can only be made postmortem or invasive methods. Treatment of the disease is limited to palliative therapy. However, current treatment protocols can prolong survival. This review provides multidisciplinary information about the pathogenesis of the disease, diagnostic methods, current protocols and the virus.