Introduction: physical assessment is essential to characterize the functional states of healthy children and of patients with concomitant nosological conditions, hence standardized exercise tests are needed. Objective: to determine the validity and reliability of cardiorespiratory indicators in Chester step test applied to healthy Chilean children. Methods: a cross-sectional study was conducted to determine the validity in a sample subgroup. A test-retest design served to estimate the inter-observer reliability of the cardiorespiratory parameters in Chester step test. Heart rate, perceived efforts and workload were also measured. The linear regression analysis between the heart frequency and the workload was made; the intra-class correlation coefficient was determined and finally the mean difference of peak heart frequency and peak VO2 between tests were estimated thorugh Bland-Altman’s method. The p< 0.05 was considered significant value. Results: Chester step test was equivalent to a submaximal test in the studied sample. Additionally, strong correlation (r> 0.9) was found between workload and heart frequency during the test. The estimated overall intra-class correlation coefficient was higher than 0.9 in both sexes. The mean difference of peak heart frequency and the VO2 measured in both tests was 1.2 beat/min and 1 mL/kg/min, respectively. Conclusions: the results indicate that Chester step test exhibits adequate validity and reliability for use in healthy Chilean children.