AIM: The importance of oral care has been recognized for the prevention of airway infections in older individuals who require long-term care. The present prospective cohort study was carried out a decade ago to identify risk factors with numerous intraoral conditions as possible predictors involved in the onset of pneumonia and acute viral respiratory infection (AVRI) in older people requiring long-term care during a 6-month follow-up period (including winter). METHODS: This study included 1785 older individuals residing in 31 long-term care facilities in which dental hygienists were involved in instruction on daily oral care. Primary end-points were development of pneumonia and AVRI during the 6-month follow-up period. Several factors related to each participant's general condition, oral environment, swallowing function and vaccinations (or lack thereof) were evaluated by calibrated dentists and dental hygienists before the study onset. RESULTS: During the 6-month follow-up period, 74 participants (4.1%) developed pneumonia, and 28 participants (1.6%) developed AVRI. Cox proportional hazard analysis showed that poor nutritional status and the presence of dysphagia were significant risk factors for pneumonia onset. The presence of dry mouth and halitosis were significant risk factors for AVRI. CONCLUSIONS: This prospective multicenter cohort study identified poor nutritional status and dysphagia as independent risk factors for the development of pneumonia, and dry mouth and halitosis as independent risk factors for the development of AVRI in older people who require long-term care and who routinely receive professional oral care. Geriatr Gerontol Int 2019; 19: 1136-1140.