This study examines the characteristics of parent-child relationships after childhood from a theoretical attachment perspective. It describes how relationships between adult children and their parents vary by age group of the child on three dimensions that were derived from attachment theory: direction, penetration and quality. Data from 4,589 respondents to the Netherlands Kinship Panel Study were analysed to describe relationships between adult-children and their parents. Analyses of covariance were used to specify differences by age group. The results showed that age had notable effects on relationships between adult children and parents, especially their direction and penetration or centrality. The direction was reversed for parents of children in the two oldest age groups. The level of penetration was lower for the older age groups, and quality was higher in the younger age groups, but the effect size was small. The age effects on the dimensions were qualified by the personal circumstances of the adult children. Having one's own children was associated with different patterns of attachment at different ages. Adult children may be an important source of support for their elderly parents and may even become 'attachment figures'. Given the current increases in longevity, there could be increasing pressure on adult children to support their parents. Attachment theory is a useful framework for studying the characteristics of inter-generational relationships, also after childhood. © 2008 Cambridge University Press.