ยฉ 2016 The Japanese Society of Veterinary Science. Since there is no available serological methods to detect antibodies to ferret coronavirus (FRCoV), an enzyme-linked immunosorbent assay (ELISA) using recombinant partial nucleocapsid (N) proteins of the ferret coronavirus (FRCoV) Yamaguchi-1 strain was developed to establish a serological method for detection of FRCoV infection. Many serum samples collected from ferrets recognized both a.a. 1โ€“179 and a.a. 180โ€“374 of the N protein, but two serum samples did not a.a. 180โ€“374 of the N protein. This different reactivity was also confirmed by immunoblot analysis using the serum from the ferret. Therefore, the a.a. 1โ€“179 of the N protein was used as an ELISA antigen. Serological test was carried out using sera or plasma of ferrets in Japan. Surprisingly, 89% ferrets in Japan had been infected with FRCoV. These results indicated that our established ELISA using a.a. 1โ€“179 of the N protein is useful for detection of antibody to FRCoV for diagnosis and seroepidemiology of FRCoV infection.