Tooth loss is a risk factor for pneumonia mortality, but it is unclear whether oral care negates excess mortality due to pneumonia among community-dwelling elderly with tooth loss. The purpose of this study was to examine the influence of oral care on the association between the number of remaining teeth and the risk of pneumonia death. We analyzed for 18,098 individuals (aged ≥ 65 years) participating in a prospective cohort study. In a 2006 baseline survey, the following data were collected: the number of remaining teeth, oral care, history of disease, smoking, alcohol drinking, education level and so forth. We also obtained data on dates and causes of death between 2006 and 2014. The primary outcome was mortality due to pneumonia. Compared with those having ≥ 20 teeth, the risk of pneumonia mortality was increased among participants having 10-19 or 0-9 teeth; the multivariate hazard ratios (HRs) (95% confidence intervals [CI]) were 1.45 (1.03-2.04) and 1.38 (1.01-1.87), respectively. Among those having 0-9 teeth, a significantly increased risk of mortality due to pneumonia was disappeared for those who brushed their teeth ≥ 2 times per day, for those with visiting a dentist, and for those with use of denture, whereas the risk persisted among those who brushed their teeth ≤ 2 times per day, for those without visiting a dentist, and for those without use of denture. Tooth-brushing, visiting a dentist or use of denture may negate the increased risk of pneumonia death among the elderly with tooth loss.