Urinary disease is the third common cause of death in dogs and the first common cause of death in cats in Japan(Inoue M. and Sugiura K., J Jpn Vet Med Assoc., 2022 ). Death by urinary disease can be due to chronic kidney disease because it is a very common condition in both dogs and cats. Appropriate diagnosis, management and monitoring of CKD are very important to prolong the life expectancy and maintain the quality of life in animals. In this lecture, you will learn the basic knowledge of CKD, its diagnosis and treatment.