The purpose of this study was to compare maximal metabolic and cardiovascular responses between a treadmill and the NordicTrack Ellipse, a combined upper/lower body ergometer. Eight untrained subjects (5 females, 3 males) volunteered for participation (M age=22.4 + 2.9 yrs). Each subject participated in two separate tests of maximal aerobic power on two separate occasions, separated by 48-72 h and presented in counterbalanced sequence. One test included increments of treadmill speed only (0%grade) until exhaustion. The other utilized a set metronome cadence with increments of resistance only on the Ellipse. Oxygen uptake (VO2) was measured continuously using open-circuit spirometry. Heart rate (HR) was monitored continuously using a Polar monitor. Values were accepted as maximal if two of the following three criteria were met: a plateau in the VO2 response with increments of work, a HR within 5% of the age-predicted maximum, a respiratory exchange ratio (RER) exceeding 1.2. Dependent t tests were used to evaluate the VO2 and HR responses. No significant (p>.05) differences were found in maximal responses between the treadmill (M VO2=39.6 + 6.8 ml/kg/min, M HR=191.14 + 12.7 b/min) and Ellipse (M VO2=39.0 + 5.2 ml/kg/min, M HR=195.7 + 10.3 b/min). It was concluded that the NordicTrack Ellipse provides a similar, but not superior aerobic stimulus to treadmill running.Keyword(s): adult fitness, assessment, exercise/fitness