Spouses frequently attempt to influence (control) or support their chronically ill partners' adherence behaviors. Studies have documented effects of spousal control and support on chronically ill individuals, but little is known about how these two forms of involvement in a partner's disease management may be associated with spouses' stress or the quality of their interactions with their ill partners. The current study sought to address this gap by examining spouses' day-to-day involvement in their marital partner's management of type 2 diabetes (n = 129). Multilevel analyses of daily diary data revealed that on days when spouses exerted control, they reported more stress and more tense marital interactions, although these associations were more pronounced when patients exhibited poor adherence, had been ill for a longer period of time, and had more comorbid health conditions. On days when spouses provided support, in contrast, they reported less stress and more enjoyable marital interactions. The findings from the current study suggest that spouses' day-to-day stress and quality of interactions with their partners are associated with spouses' involvement in their partners' disease management, with health-related social control and support exhibiting distinctive associations.