In Korea, the number of companion animals, especially dogs and cats, is rapidly increasing mainly due to the increase in the number of nuclear families and single-person households. Nevertheless, only one study has explored the future market size of pet related industries by applying compound annual growth rate to the market size in 2012. The objectives of this study are to update the information on the market size of pet related industries and to estimate the potential market size in the future using a bass diffusion model. The results of this study indicated that a total of 9.32~9.97 million dogs and cats was estimated to live in Korean households as pets in 2018. This number will increase to 11.55~16.49 million in 2027. The market size of pet related industries in Korea was estimated to 1,544 billion KRW in 2018 and 3,498 billion KRW in 2027.