We analyzed the 5-year longitudinal relationship between cardiorespiratory fitness (CRF) and cardiovascular diseases (CVD) risk factors in children. A total of 153 students (66 boys and 87 girls) were evaluated in 1998 and 2003. Multilevel modeling was used to determine the effect of CRF across time (Model 1, adjusted for time and Model 2 - Model 1 with further adjustment for gender and age). In both models, a significant main effect was found for body mass index (BMI) (P ≤ 0.05). Data showed that in children, lower levels of CRF are associated with higher levels of BMI over a 5-year follow-up period. © 2008 Wiley-Liss, Inc.