The number of older adults is increasing dramatically, and their children are often their primary social contacts. This means that the older parent-child relationship is of vital importance. Our aim was to examine how relationship quality of older parent-child dyads is reflected through language in an interaction task. We selected two parent-child dyads that represent contrasting cases in terms of relationship quality. The interaction task consisted of a 10-minute discussion between parent and child about a difficult situation the parent faced. Data were analyzed using a Conversation Analysis approach. In the dyad with good relationship quality, the discourse was characterized by validating difficulties and co-constructing shared understanding; in the dyad with poor relationship quality, there was an ongoing process of redefining the issues presented. The present methodological approach proved to be useful for analysing dyadic interactions in advanced age and to delineate the co-construction of discourse and relationship.