Obesity is a complex and increasingly prevalent health disorder that is associated with a wide range of medical, social, and psychological difficulties. People are more likely to be obese if they consume an energy dense diet but do not engage in physical activity. Research has indicated that interventions, when implemented during childhood, have long-term outcomes that are superior to interventions implemented in adulthood. This research piloted a behaviourally based intervention programme, with parents as the agents of change, to promote a lifestyle change for inactive children. The programme focussed on increasing physical play (lifestyle activity) and on decreasing sedentary behaviour (an obesity promoting behaviour) during children's after school leisure time. The intervention was investigated using three case studies. Although no conclusive evidence was gained regarding the effectiveness of the pilot programme there was some evidence that children participating reduced their amount of sedentary behaviour and increased the amount of time they spent in physical play. There was also evidence that parents were able to administer the programme and that they found it useful. The results from the present study suggest that the development and application of parent administered behavioural programmes, in the form of packaged interventions to prevent child obesity, warrant further investigation both in terms of the benefits and costeffectiveness it could offer parents and practitioners alike.