Why has an increase in personal piety among Indonesia's Muslims not translated into electoral gains for Islamic political parties? To help explain this conundrum, this article focuses on the role of Indonesia's mass Islamic social organisations, Nahdlatul Ulama (NU) and Muhammadiyah. Using a political economy lens, it argues that control over state resources and the provision of social welfare facilities have helped political parties maintain power over the years and that NU and Muhammadiyah have at times played important mediating roles in this process. Extending this analysis into Indonesia's contemporary politics, it then proposes that since 2004 in particular, the health and education facilities provided by NU and Muhammadiyah are becoming less important to ordinary people in relation to the services provided by the state. It concludes that this trend has weakened the ability of these organisations to channel public support to political parties/candidates and is one reason why Islamic parties have not been able to capitalise on increased religiosity in the social sphere.