The assessment of parent-infant relationships is an important process in safeguarding and promoting the health of children. There is compelling evidence of the importance of early attachment on the infant's neurological and emotional development. Health visitors are uniquely well placed to identify problems in the parent-infant relationship and to help improve its quality. This study explored health visitors' perceptions of their role in assessing and supporting parent-infant relationships and their views of their own educational needs. Semi-structured interviews were conducted with a purposive sample of six experienced health visitors. Health visitors used multiple sources of information in assessing parent-child relationships, including direct observation of behaviour, assessment of known risk factors, knowledge of norms and 'intuition'. Strategies to support the parent-infant-relationship included parenting support at home, listening support, encouraging parenting group attendance and referral to other support agencies. Health visitors reported a lack of training in parent-infant relationships. General agreement is required nationally and locally on educational and clinical experience prerequisites for this aspect of the health visitor role. Reduced client contact, as well as a lack of training in and use of specific 'relationship assessment' tools, may affect this. The Solihull Approach to mental health may be useful for informing future health visitor training and practice.