Introduction: Childhood obesity has a high prevalence across the Western world, and infancy has been identified as being important for establishing later eating patterns. There have to date, been few attempts to develop or evaluate programs aimed at the primary prevention of obesity. Aims: To pilot and evaluate a primary preventive health visitor delivered intervention focusing on five key lifestyle areas (parenting, emotional well-being, eating behaviour, physical activity and nutrition), in terms of its impact on nutrition and physical activity patterns in infants at increased risk of obesity. Method: The study was conducted in two phases. The first phase piloted the intervention with eight families; the second phase comprises an ongoing feasibility trial in which sixty-two women (BMI > 35 kg/m2 ) were recruited at booking and randomized into intervention or usual care pathways following the birth. A mixed methods approach is being used to ascertain objective outcomes including weight status and to evaluate acceptability of the program. Findings: The pilot study demonstrated that families found the program acceptable, valuing in particular the approach of the health visitor, with its emphasis on non-judgemental listening, partnership working and shared problem-solving. A range of benefits was also identified including increased knowledge of appropriate foods for their children and the family as a whole. Conclusions: To our knowledge, this will be the first health visitor-led primary prevention intervention in the early years internationally. The results from the feasibility trial will provide the data needed to seek funding for a definitive effectiveness RCT with infants at increased risk of obesity.