Purpose. The goal of this study was to compare two sub-maximal exercise tests used in predicting VO2max.abs, the 3'Bike Test, which has not previously been used as a functional test, and the Astrand Submaximal Bike Test. Methods. 1492 athletes aged 16-35 years were tested. After anthropometrical measurements, each athlete performed the new 3'Bike Test, and after resting for one hour, they performed the Astrand Bike Test. Results. Based on the data collected, when looking for correlations between the two tests' variables that indicate VO2max.abs, finds that the 5th minute of Astrand Bike Test realized its best correlation with the 3rd minute of the 3'Bike Test. This significant partial correlation between the 5th minute of the Astrand Bike Test and 3rd minute of the 3'Bike Test points to some similarities between these two tests. Linear regression of the data indicates that the system of predictive variables of the 3'Bike Test explains for 36.4% of total variability of the dependent variable (VO2max.abs) with a lower standard error of estimate of 0.247. Whereas the system of predictive variables of the Astrand Bike Test explains for 31.9% of total variability, with a standard error of estimate at 0.256. The third minute of the 3'Bike Test, with a beta-coefficient of -0.54, indicates better predictive influence of VO2max.abs when compared to other test variables. Conclusions. According to the above-mentioned results, it can be concluded that the new applied functional test, the 3'Bike Test, better predicts VO2max.score when compared with the Astrand-Bike Test.