OBJECTIVES: As populations age, there will be a need for more volunteers in social welfare, and consequently a need to better understand potential effects of volunteering for older people. Whilst there is a body of international literature exploring health benefits of volunteering in later life, there are currently no longitudinal studies of Australian populations. Internationally, there is a lack of studies focusing on older women, who comprise the majority of the ageing population. The aim of this article was to explore the relationship between volunteering and psychosocial and health factors for a cohort of older Australian women over time. METHOD: Data for this study were from the oldest cohort of Australian Longitudinal Study on Women's Health, a 20-year longitudinal survey of Australian women aged 70-75 years in 1996. Volunteering status was the factor of interest and study factors included a broad range of demographic, health and social factors. A longitudinal model was developed for mediators of volunteering over time. RESULTS: Of 7088 women in 2005, 24.5% reported actively volunteering, 15.5% were continuing, 7.5% were new, 15.3% were intermittent and 34.7% had never been volunteers. Volunteering was associated with increased quality of life and social support. Women were more likely to continue volunteering over time if they lived in a rural area, had higher socioeconomic indicators, and better levels of physical and mental health. CONCLUSIONS: This study contributes to the literature on the relationship between volunteering and health for older women. Understanding the potential health implications of volunteering is a critical issue in current policy debates.