Recombinant canine coronaviruses, resembling the transmissible gastroenteritis virus of swine (TGEV) in a 5โ€ฒ fragment of the S glycoprotein, have been detected recently and showed to be present in canine populations. The 5โ€ฒ fragment of the S protein (Sโ€ฒ) of a TGEV-like canine coronavirus (CCoV), strain 174/06, was expressed in an Escherichia coli cell-free system. The purified recombinant polypeptide was employed to develop an ELISA test for the detection of TGEV-like CCoV-specific antibodies in dog sera. Four canine sera positive for TGEV-like CCoV, six sera positive to classical CCoV-II strains and 10 negative control sera were examined. The recombinant Sโ€ฒ was not recognized by antibodies to classical CCoV-II, as only sera from dogs infected experimentally with TGEV-like CCoV reacted strongly with the recombinant Sโ€ฒ polypeptide whereas dog sera with antibodies to classical CCoV-II did not react. As classical CCoV-II and TEGV-like CCo. Vs are related antigenically, the recombinant Sโ€ฒ ELISA is a useful method to investigate serologically the prevalence of TGEV-like CCo. Vs in dogs.