espanolObjetivo Examinar la asociacion entre capacidad cardiorespiratoria y muscular y la presencia de obesidad y otros factores de riesgo cardiovascular y metabolico en escolares. Material y metodo: Estudio de corte transversal, realizado en 336 ninos y ninas escolarizados en los grados 5o y 6o de colegios publicos de Bucaramanga, Colombia. Resultados: Se encontraron correlaciones inversas significativas entre indice de masa corporal (IMC) y fuerza de empunadura ajustada por peso (-0.532) (P Conclusion: La obesidad evaluada por el IMC y el porcentaje de grasa corporal se relacionan inversamente con la aptitud muscular y cardiorrespiratoria en escolares EnglishObjective: To examine the association between cardio respiratory and muscular fitness and the presence of obesity and other cardiovascular and metabolic risk factors in school children. Material and method: Cross-sectional study, conducted in 336 school children (boys and girls) in grade 5o and 6o of public schools in the city of Bucaramanga, Colombia. Results: Significant inverse correlations were found between body mass index (BMI) and grip strength adjusted for weight (-0532) (P Conclusion: Obesity assessed by BMI and body fat percent is inversely related with muscular and cardio respiratory fitness in Colombian school children.