Selecting the appropriate reference values for maximal oxygen uptake (VO2peak) is of pivotal importance in the differential diagnosis of abnormal findings in cardiopulmonary exercise testing. The currently used reference values proposed by Jones et al, Hansen et al, and Fairbarn et al, which are based on cycle ergometry, present significant interstudy differences and cannot be applied to sedentary subjects, whereas reference values for several other variables have not been assessed at all, making it difficult to deduce valid conclusions. We studied 68 normal male adults, aged 18–48 years, who reported absence of systematic exercise. A progressive incremental exercise of 20 Watts/min up to exhaustion was performed, using a cycle ergometer and a mixing chamber system (EOS Sprint, Jaeger). Maximal oxygen uptake, heart rate, performed work, tidal volume, ventilation, oxygen pulse, lactate threshold and respiratory reserve were measured at peak exercise. The height of the subjects ranged from 166 to 194 cm and the weight from 57 to 95 kg. Smokers and subjects with exertional dyspnea or cough were included in the study, provided that resting spirometry was normal. In overweight subjects, Bruce’s correction for weight was used. Predicted values for VO2 proposed by Fairbarn, Jones and Hansen were found to be systematically higher by 45%, 25% and 6%, respectively. VO2peak varied according to age and height, while maximal heart rate was predicted by age alone. Normal values for respiratory reserve set at >11 Lit/min showed specificity of 99% and for VT/FVC ratio at >30% had a specificity rate of 96%. Lactate threshold appeared at 80% of VO2peak, with a lower limit of 56% (SD 9%). In conclusion, predicted values proposed by Hansen et al are comparatively more representative of the Greek sedentary general population, but still not ideal. The results of the present study are proposed as useful reference values in the evaluation of cardiopulmonary exercise testing in the average Greek population. Pneumon 2004, 17(1):55-63.