We investigated 23 patients with combined influenza virus and bacterial pneumonia of whom 10 patients were men, 13 were women and the mean age was 78.0 years old. The causative virus of 12 patients was type A, that of 10 patients was type B, and 1 patient was unclassified. S. pneumonia was isolated from 12 patients, S. aureus and H. influenza was isolated from 2 patients. B. Catarrhalis and Milleri spp was isolated from one patient each. The mean interval between onset of influenza and influenza pneumonia was 2.09 days. Fourteen cases developed pneumonia within 2 days after influenza infection. In particular, all nine cases with chronic respiratory disease developed pneumonia within 2 days. All cases except one were treated with oseltamivir and antibiotics, resulting in cure. These data suggest that patients with chronic respiratory disease might develop influenza pneumonia earlier than past reported cases.