Grants and services provided by the government may crowd out informal arrangements, thus weakening informal caring relations and networks. In this paper, we examine the impact of social security expansion on neighborhood cohesion of elders using China's New Rural Pension Scheme (NRPS), one of the largest existing pension program in the world. Since its launch in 2009, more than 400 million Chinese have enrolled in NRPS. We use two waves of China Health and Retirement Longitudinal Study (CHARLS) to examine the effect of pension receipt on two dimensions of neighborhood cohesion among older adults, i.e. participation in collective recreational activities (e.g., socializing and organizational activities) and altruistic activities (e.g., helping those in need in the community), and the frequencies of these activities. Employing an instrumental variable approach, our empirical strategy addresses the endogeneity of pension receipt via exploiting geographic variation in pension program roll-out. We find evidence that receiving pension only slightly reduces collective recreational activities while significantly crowding out altruistic activities in the communities.