Having an adolescent with Type 1 diabetes (T1D) can be stressful for the entire family. This study examined the impact of parents' relationship maintenance on their ability to manage the conflict associated with their child's T1D, the parents' physiological health (inflammation), and the relationships within the family. Sixty couples and their adolescent children with T1D participated. The couples engaged in a stressful conversation about their child's T1D in their home, followed by random assignment to a 2-week intervention designed to increase the relationship maintenance in the marriage. Results from the home visit revealed that when husbands and wives received greater maintenance from each other the past month, they perceived less conflict when talking about their adolescent's T1D, which was associated with less relational load and lower levels of C-reactive protein (CRP). For wives, greater relationship maintenance was also directly associated with less relational load and lower CRP levels. In addition, the relationship maintenance received was directly and positively associated with parent-child relationship quality for fathers, but this association was mediated by interparental conflict for mothers. Finally, the 2-week intervention reduced parents' relational load and the number of stressful conversations and improved the mother-adolescent relationship but did not significantly reduce parents' CRP. (PsycInfo Database Record (c) 2020 APA, all rights reserved).