Objective: The present study aims to investigate the factors related to self-rated ikigai (purpose in life) among older residents participating in hillside residential community-based activities in Nagasaki City.Methods: A self-administered anonymous questionnaire survey was carried out with older residents participating in two hillside residential community-based activities in Nagasaki City, Japan. The questionnaire included questions on sociodemographic information (age, sex, family structure, education, and self-rated economic satisfaction), self-rated health, mental health status measured using Geriatric Depression Scale-15 (GDS-15), and self-rated ikigai score that was estimated using a visual analog scale.Results: A total of 32 older residents (7 males, 25 females) participated in the questionnaire survey. Although self-rated ikigai score was not associated with sociodemographic factors, there were associations between the score, self-rated health (P=0.001), and mental health (GDS-15) (P=0.015). Statistically significant correlations between self-rated ikigai score and social participation (ρ=0.426, P=0.017), self-rated health (ρ=−0.485, P=0.007), and mental health (GDS-15) (ρ=−0.523, P=0.007) were observed.Conclusion: Increasing social participation may increase individual ikigai, preventing poor self-rated health and low mental health status in older people. Maintaining their social participation in the community might be effective for the health promotion of older residents in hillside residential areas of Nagasaki City.