This study explored the experiences of mothers of children with cystic fibrosis (CF) in postdivorce family structures. In-depth interviews of mothers were conducted by registered nurses with expertise in CF. Interviews focused on responsibility for care of the CF child within the context of postdivorce families (e.g., extent of nonresidential fathers’ involvement in children’s care, communication between households). Interviews were audiotaped and transcribed verbatim. The constant comparison method was used for analyzing interview data. Marital transitions contributed to the closeness between mothers and children with CF, but they also added to the mothers’ sense of being overwhelmed with responsibilities. It is likely that children and mothers are more at risk for stress-related problems when mothers are overburdened by the demands of caregiving, earning a living, and other responsibilities.