Seoul virus glycoprotein Gn is a major structural protein and candidate antigen of hantavirus that induces a highly immunogenic response for hantavirus vaccine. In this study, a replication-competent recombinant canine adenovirus type-2 expressing Gn was constructed by the in vitro ligation method. The Gn expression cassette, including the human cytomegalovirus (hCMV) promoter/enhancer and the SV40 early mRNA polyadenylation signal, was cloned into the SspI site of the E3 region which is not essential for proliferation of CAV-2. Expression of Gn was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.