A piglet developed respiratory distress followed by difficulty in standing and unsteady gait. The lesions were characterized by polioencephalomyelitis with the predominant distribution in the brain stem, as well as lymphocyte depletion and histiocyte infiltration with cytoplasmic inclusion bodies in the lymphoid tissues throughout the body and interstitial pneumonia. Porcine teschovirus (PTV) antigens were found in the former lesions and porcine circovirus 2 (PCV2) in the latter two lesions. PTV genes were detected from the diencephalon. The results suggest that the piglet was concurrently affected with polioencephalomyelitis due to PTV and postweaning multisystemic wasting syndrome (PMWS) associated with PCV2. They also suggest that the immunosuppressive condition developing in PMWS may have facilitated the infection of the brain with PTV.