Influeza type A virus have been worldwide problematic in animals as well as in humans. In this study, the use of reverse-transcriptase polymerase chain reaction (RT-PCR) was described for detecting influenza virus type A. The primer of RT-PCR was designed from an nonstructural (NS) gene of Influenza A virus. By RT-PCR, a product with the size of 189 bp was detected only when influenza virus type A was used as template. No products could be detected with Influenza virus type B as well as other respiratory pathogens. The detection limit of the RT-PCR was up to $10^{0.3}TCID_{50}$ which is comparable to the sensitivity of cell culture method. The RT-PCR could detect the influenza A virus from nasal turbinates of the ferrets infected with influenza virus type A not type B.