The purpose of this study was to determine the agreement of physiological parameters measured during exercise testing on 2 devices at established power outputs (POs). Ten trained male cyclists were recruited. The devices used for comparison were the Lode stationary bicycle ergometer (SBE) (Lode Excalibur) and the PowerTap Pro+ (BPT) (Saris Cycling Group) mobile ergometer. The physiological parameters recorded at established PO (50, 100, 150, 200, 250 W) were heart rate (HR), oxygen consumption ((Equation is included in full-text article.)), pulmonary ventilation (VE), blood lactate, and ratings of perceived exertion (RPE). Subjects were randomized once to the SBE and 3 times to a bicycle equipped with a BPT. After 15 minutes of unloaded pedaling, the trial began with 5 minutes of cycling at 50 W. Intensity increased by 50 W every 5 minutes up to 250 W. Physiological measures were recorded at each PO. Bland-Altman plots were constructed including computation of the ratio of half the range of limits of agreement and the mean of the pairwise means along with bivariate regression calculations for analysis of the linear association between device measurements. Moderate to good agreement was found for HR with agreement improving as PO increased. Comparisons of (Equation is included in full-text article.)found agreement increased as the PO increased. VE, RPE, and lactate did not consistently provide similar measures across trials. The level of agreement between HR and (Equation is included in full-text article.)when comparing the SBE and BPT suggests that the PowerTap Pro+ is a sufficient tool for estimating PO and associated physiological parameters in the field.