The study compares the formal and informal social participation of 60-69 year olds in The Netherlands in 1992 and 2002, and examines which attributes of the two cohorts favour social participation. Using data from the Longitudinal Aging Study Amsterdam, it was found that cohort differences in formal participation (as members of organisations, in volunteer work and in religious organisations) and in informal participation (having a large social network, and in cultural and recreational activities) associated with cohort differences in individual characteristics (level of education, health, employment status and marital status). Descriptive analyses showed an increase between 1992 and 2002 in all forms of participation except religious involvement. The 2002 cohort members were more educated and more engaged in employment, but in worse health and had a higher prevalence of divorce than the 1992 cohort members. Logistic regression analyses showed that the positive effect on social participation of the recent cohort's higher educational level was suppressed by the negative effect of their worse health. Being divorced had mixed effects on formal and informal participation, but the difference in the number of divorcees did not explain cohort differences in social participation. Interaction effects showed that the influence of sex and health on volunteer work and religious involvement changed over time. The paper concludes with a discussion of the prospects for higher levels of formal and informal social participation among future cohorts of young-older people. © 2010 Cambridge University Press.