Background: This study investigated physical activity and dietary intake of children aged 9-11 years, and the influence of peers on these behaviours over a 2-year period. Methods: A total of 106 (64 girls; 42 boys) children were investigated annually, over 2 years. Measures included physical activity (sealed pedometer), self-report measures of dietary intake and physical activity, and a peer influence questionnaire. Anthropometric measures of height and weight were also obtained. Results: The findings reveal insufficient energy intakes, physical activity levels and fruit and vegetable consumption but high intakes of saturated fat and sodium, over time, in both boys and girls. Both male calcium and female iron intakes were also of concern. Throughout the survey, peers were found to influence physical activity behaviour but not dietary intake. Conclusions: The fact that youth consistently failed to meet established nutrition and physical activity recommendations highlights the importance of promoting physical activity and healthy eating to children younger than 9 years of age. The finding that peers significantly influence physical activity behaviour over time should be considered when designing new physical activity interventions aimed at young people.