Childhood obesity is associated with a number of modifiable risk factors that can be identified during infancy or earlier. In the UK, health visitors advise parents about infant feeding, but little is known about their role in obesity prevention. The aim of this study was to investigate the beliefs and current practices of UK health visitors in relation to recognising and intervening with infants at risk of developing obesity. Thirty members of the health visiting team were interviewed. The interviews were audio-recorded and transcribed verbatim. Thematic analysis was applied using an interpretative, inductive approach. Health visitors were aware of some of the modifiable risk factors for childhood obesity such as infant feeding practices. They felt they had a role in advising parents about diet but did not formally identify and/or intervene with larger infants. Infant overweight was considered a sensitive issue that was difficult to raise with parents. They believed some parents preferred larger infants and were unaware that their feeding practices might be contributing to obesity risk. A need for training and guidance was identified together with strategies to overcome system barriers. Health visitors do not currently target parents of infants at risk of obesity largely because they do not perceive they have appropriate guidance and skills to enable them to do so. There is an urgent need for tools and training to enable all health care professionals to recognise and manage infants at risk of developing obesity without creating a sense of blame.