Overweight in childhood and adolescence is a major public health problem due to its medical and psychosocial consequences. The aim of this study was to investigate overweight and life style factors in children aged 10. The sample consisted of 138 children 10 years of age from three public primary schools in southern Sweden from whom data on height, weight, Body Mass Index (BMI) and life style were obtained during 2003–2004. Differences in life style factors between the overweight and the non-overweight children were investigated using the chi-square test and Fisher exact test. The association between life style factors and overweight was studied using multivariate logistic regression analysis. Omitting lunch at school and feeling tired at school were found to be associated with overweight. Headache and the experience of being bullied were significantly more common among the overweight children. Overweight was found in 24% of the children, a fourth of whom (6%) were obese. This is important problems that school nurses need to confront. A new and interesting finding obtained was that omitting lunch at school was associated with overweight. Additional longitudinal studies of the impact of life style factors on paediatric overweight are needed to assess school-based preventive programmes.