In the nursing home belonging to our hospital, an outbreak of influenza A (H3N2) occurred in January 1995, and we studied 23 elderly residents with influenza A infection. Twenty three residents with influenza A (8 males and 15 females) ranged in age from 67 to 95 years (average 83.1 years), 91.3% of them were bedridden. And all had underlying medical conditions with neurologic, cardiac, orthopedic, being the most frequent. The most common complaints were fever (100%), followed by cough (95.7%), sputum (60.9%), but sore throat was significantly less frequent. Influenza A virus was isolated from throat swab specimens from 6 of 18 ill patients. Fourteen persons were hospitalized and 2 of them had pneumonia, but nobody died. The levels of CRP, WBC were significantly high in the influenza group, as compared to the non influenza group. So this result suggested that influenza A infection among elderly subjects was apt to cause bacterial infection such as bronchitis and pneumonia. This outbreak was caused by contact from the staff to residents, so we think the health care of the staffs and prevention of influenza should be a high priority in nursing homes.