AIMS: To measure physical activity by means of daily pedometer steps, body composition, expressed as body mass index (BMI) and bioelectrical impedance as percent body fat, and perceived physical self-esteem and additionally, to evaluate eventual predictors for a healthy lifestyle i.e., highly physically active, normal weighted and a high physical self-esteem in a follow-up group. METHODS: During autumn 2000 physical activity level was assessed and BMI was calculated in 871 children aged 7-14 in south eastern Sweden and in 501 of these, physical self-esteem were also assessed. During autumn 2003 a total of 375 adolescents aged 15-18 were assessed using the same methodology and additionally percent body fat was measured. Ninety-three of these adolescents (46 girls), were also measured in 2000 and they formed the follow-up group. RESULTS: In the follow-up group a significant increase in BMI and stability in physical self-esteem in boys and girls, and in boys a significant decrease in daily steps was found 3 years later. Strongest predictor to be highly physically active, maintain normal BMI and high self-esteem 3 years later, i.e., to have a healthy lifestyle, was for girls increased self-esteem and for boys a decreased BMI. CONCLUSION: Consequently, for a healthy lifestyle, promoting physical self-esteem in girls and weight control in boys is of great importance in early adolescence.