Influenza A virus (IAV) and Respiratory syncytial virus (RSV) are two of the most common viruses that cause respiratory infections affecting young children and the elderly. Studies are now showing the presence of dual infections. Although the importance of CD8 T cell immunity to pulmonary virus clearance is well documented, little is known of the immune response to both the primary and secondary viruses. With that rationale in mind, our goal was to determine if the response of virus specific CD8 T cells is altered due to pulmonary virus co-infections. In this study, we utilized the intranasally model of IAV and RSV infection together morbidity and mortality measurements as well as flow cytometry based analysis of dendritic cells and virus-specific CD8 T cells (tetramer staining) to determine if co-infections alter the disease severity underlying. Our results suggest that the severity of IAV infections is dramatically altered to result in more severe (RSV as a secondary virus) or less severe (RSV as a primary infection) disease based upon the timing of a co-infection with RSV. Further our results show that IAV alters the magnitude of RSV-specific CD8 T cell responses. Together these results suggest that co-infections affect the severity of viral infections as well as the immune response generated to them.