Background: Health visitors (HVs), also known as public health nurses, in the UK provide a universal community-based service to preschool children and their parents. Since they have ongoing supportive contact with almost all mothers and young children they have opportunities to identify problems in the parent-infant relationship: for example during developmental screening, home visits and immunisation clinics. Research into the role of screening for problems in the parent-child relationship in early childhood is sparse and little is known about how such problems are currently identified in the community Objective: To explore the approaches taken by health visitors (HVs) to identifying problems in the parentchild relationship Design: focus group study.Setting: Glasgow, Scotland Participants: 24 health visitors sampled purposively Results: Multiple sources of information were used by health visitors in assessing parent-child relationships.These include use of known risk factors, knowledge of local norms, direct observations of behaviour, reflection on the relationship between the parent and health visitor, as well as more intuitive reactions. In many cases understanding difficulties in parent-child relationships involved piecing together a jigsaw over a considerable time span. Continuity of relationships appeared to be crucial in this task. Home visits were described as the most informative setting in which to develop an understanding of the parent-child relationship. Participants reported a lack of formal training in the assessment of parent-child relationships and were keen to obtain more training.Conclusions: Health visitors use complex strategies to integrate information about parent-child relationships.These strategies are acquired in a variety of ways, but receive little emphasis during basic professional training.