My paper entitled “(Infra)structures of Volunteering” has been accepted for publication to the ACM Conference on Computer-Supported Cooperative Work and Social Computing. This research was carried out in collaboration with Dr. Matthias Korn and Zheng Yao, an undergraduate researcher from Cornell University. This paper reports on the results of a diary study of the everyday volunteering and help giving of individuals in the millennial generation. We describe the breadth of work structures implicated in volunteering, from planned and systematic to spontaneous and unpredictable; the social structures implicated in volunteering, including relationships among volunteers and relationships between volunteers and beneficiaries; and unpack the interdependencies between the two. We analyze the roles that technology plays in volunteering with a particular focus on the forms of infrastructure that are constituted through the work and social structures of this philanthropic activity. Finally, we reflect on design opportunities for infrastructures where work and social structures meet to support more everyday, ubiquitous forms of volunteering.