Physical activity and psychological well-being contribute to positive lifestyle and well-being in youngsters who have Type 1 diabetes. The aims of this study were to objectively assess the physical activity levels of children with Type 1 diabetes, and investigate associations between physical activity levels, psychological well-being and HbA(1c). Thirty-six children, mean age 12.8 years, participated in the investigation. Physical activity was assessed using heart rate monitoring over four days. Children further completed the Diabetes Quality of Life for Youths Questionnaire, the Physical Self-Perception Profile for Children and the Self-Efficacy for Diabetes Scale. Routine outpatient HbA(1c) measurements were recorded. There were no significant associations between psychological well-being and physical activity, or HbA(1c) and physical activity, thus suggesting physical activity does not directly relate to psychological well-being in children with Type 1 diabetes. It may be that the effect of physical activity differs from that in children without Type 1 diabetes because of the place of physical activity within diabetes management and the need to balance this with insulin dosage and dietary intake to maintain blood glucose levels.