Discontinuity of grandparent-grandchild relationships has been largely overlooked in social science research, despite the fact that the salience of the grandparent grandchild attachment bond is the subject of considerable discussion. This article reports the results of an exploratory study of grandparent-grandchild contact loss, by means of a survey of the core membership of five “grandparent rights” groups across Canada. As reflected in the particular concerns of this membership, there are four primary circumstances associated with grandparent loss of contact with grandchildren: parental divorce, conflict with both parents, death of adult child, and stepparent adoption following remarriage. Grandparents whose adult children are noncustodial parents (mostly paternal grandparents) are at high risk for contactloss, and adult children-in-law appear to be the primary mediators in the ongoing grandparent-grandchild relationship. Disrupted grandchild access is seen as having profound negative consequences for grandparents, and this has important implications for socio-legal policy and therapeutic practice.