This paper considers a dimension of social life that has been largely neglected in the research literature on ageing, older men's involvement with informal associations. These affiliations represent an under-valued resource which may contribute to the quality of life of older men by facilitating social interaction and providing a context for continued social productivity. Using the British Household Panel Survey for 1999, we explore the engagement of men aged 65 or more years with civic groups (such as political parties or voluntary agencies), religious organisations, and sports and social clubs. Involvement in civic and religious groups and sports clubs is common among middle class older men, while social club membership is common among working class men. Only a small amount of these differences can be explained by variations in health, income and access to private transport. Compared with partnered older men, widowers are more likely to be involved with sports and social clubs, while men who are divorced or never married are less likely to be a member of any informal group.