A substantial body of research examines volunteerism via surveys of individual volunteers or volunteer organizations. The authors argue that researchers must expand this conceptualization of volunteering to include the interactive process between the volunteer and the organization. Using structuration theory as a guiding framework, the authors examine how volunteers' behavior is both shaped by and also affects the way in which two organizations are structured. In this comparative case study, the authors utilize participant observation, interviews, and archival analysis to illustrate this interaction in two organizations, a no-kill cat shelter and a resource organization for women who partner with women. They find that the character of the labor process, and specifically whether it entails the expenditure of emotional labor, leads to either burdensome or rewarding volunteer experiences. The authors further underscore the importance of examining emerging trends in "episodic volunteering" and shifts in nonprofit organizations toward more bureaucratized business forms.