Background: A reference set of data of normal values of newly developed cardiopulmonary parameters of exercise testing in an 8-18-year-old population is lacking. Patients and methods: Cardiopulmonary exercise testing was performed in 175 healthy school children (8-18 years old). Continuous electrocardiography was performed, and minute ventilation, oxygen uptake (VO 2 ), and carbon dioxide (CO 2 ) production were measured continuously with a respiratory gas analysis system. Results: Peak VO 2 /kg did not change with age, whereas the ventilation to carbon dioxide exhalation slope was lower in the older children. The decline in heart rate during recovery was much faster in the youngest children. Linear regression analysis showed a significant effect of age on: peak work rate (WR peak ) and WR peak /kg, ventilation to carbon dioxide exhalation slope, heart rate recovery, and VO 2peak (boys only) (All P < 0.001). The ÁVO 2 /ÁWR slope remained constant throughout all age groups. Conclusion: This study comprehensively provides a reference set of data for the most important cardiopulmonary variables that can be obtained during exercise testing in children.