Objective : The purpose is to identify the general characteristics, oxygen saturation levels, and cognitive function scores of elderly individuals according to their smoking status, demonstrate the clinical importance of smoking cessation for their oxygen saturation and cognitive function, and provide academic baseline data for the future development of community-based dementia prevention education and tailored smoking cessation intervention programs for high-risk groups. Methods : This study was conducted from January to February 2026 with 108 elderly residents of the community selected as participants. Descriptive statistics were performed for the elderly's major variables, and differences in oxygen saturation and cognitive function according to smoking status were analyzed using one-way ANOVA. An analysis of the association among major variables was conducted. An eta(η) coefficient was calculated between the categorical variable smoking status and the continuous variables oxygen saturation and cognitive function scores, and Pearson correlation analysis was conducted between the two continuous variables, oxygen saturation and cognitive function scores. The effects of smoking status on oxygen saturation and cognitive function were analyzed using multiple regression analysis. Results : Statistically significant differences were observed among the groups based on smoking status for both oxygen saturation(F=14.45, p<.001) and cognitive function scores(F=17.45, p<.001). Post hoc analysis showed that oxygen saturation was significantly higher in non-smokers (96.5%) and former smokers (96.2%) than in current smokers (93.2%), and cognitive function scores were higher in non-smokers (25.6), former smokers (23.4), and current smokers (21.1), respectively. The association analysis showed a strong association between smoking status and oxygen saturation and cognitive function scores, and the multiple regression analysis identified smoking status as a major related factor that has a significant negative effect on oxygen saturation and cognitive function. Conclusion : Smoking in the elderly creates a chronic low-oxygen environment in the body, adversely affecting brain tissue and becoming a key factor in promoting cognitive decline. And in the case of ‘Former smokers' there was a tendency for oxygen saturation and cognitive function to be partially preserved. Therefore, in community dementia prevention and management programs, smoking cessation among the elderly should be treated as an essential intervention factor, and, in addition to smoking cessation programs, tailored cognitive rehabilitation interventions such as occupational therapy to maintain daily living functions should be provided concurrently.