They examined co-parenting alliance based on information provided by 57 incarcerated parents and their corresponding child caregivers who took part in the Messages Project, in which incarcerated parents video recorded greetings to children that were then mailed home. We assessed perceptions of co-parenting alliance, measured by the Parenting Alliance Measure, and levels of child contact from both parents and caregivers. They also observed expressions of positive and negative attitudes that prisoners expressed regarding the home caregiver during the video recording. Incarcerated parents reported more frequent phone contact with children and more frequent letter-writing to children than did home caregivers. Incarcerated parents likewise reported higher levels of co-parenting alliance with the home caregiver in comparison to the assessment of co-parenting alliance reported by the home caregiver. Among children observing the video recorded message, a more positive co-parenting alliance between their parent and home caregiver was associated with increased positive mood. More frequent displays of negative attitudes toward caregivers during the recordings were associated with more negative mood indicators among children. Results suggest the importance of a strong co-parenting alliance between incarcerated parents and home caregivers, but imply that incarcerated parents may have a more optimistic view of their connection home than is the case for collaborating caregivers.