Influenza A virus, (H1N1 Subtype), was identified as the cause of outbreaks of febrile respiratory infection in Mexico, the US, Canada and elsewhere during the spring of 2009. In Korea, a novel virus infection showing many variable complications was also pandemic. We report two cases of spontaneous pneumomediastinum, complicating viral pneumonia, caused by Influenza A virus, (H1N1 Subtype).