Although government-organized volunteering is common in China, the Chinese government has also sought to encourage the development of grassroots volunteer service organizations (VSOs) given the tremendous social service burden and the complexity of social governance. Motivated by the lack of systematic studies on volunteering in China, this study explores predictors of volunteering in urban China using data from the 2013 Survey on Philanthropic Behaviors of Urban Citizens in China. The findings indicate that generalized trust, membership in the Chinese Communist Party and type of work unit are significantly associated with the government-organized volunteering. Similar to Western countries, education, religiosity and social capital variables all help in explaining grassroots VSO-organized volunteering. Interestingly, the association between grassroots VSO-organized volunteering and trust in the central government with regard to both participation probability and time devoted to volunteering is significantly positive, whereas the association between grassroots VSO-organized volunteering and trust in local government, for both participation probability and time devoted to volunteering, is significantly negative.