The VO2max response of 12 well-trained and highly motivated college males was measured using two treadmill protocols: horizontal (H) and inclined (I). The duration of each test averaged 10 min. In the H test the treadmill bed was horizontal with the running rate held constant for the first 6 min, after which time it was increased at 1-min intervals to near maximal subject running speed, according to the HR response, until exhaustion. The I method simulated the protocol of Costill and Fox, with the treadmill speed at about 80-90% of mean maximal running rate established from 12- and 15-min track runs. The treadmill bed was held horizontal during the first 4 min, after which time it was elevated to 4% and elevated 2% each 2 min thereafter until exhaustion. No significant differences were found in VO2max, 4.267 1/min (I), and 4.192 1/min (H), average max HR, 190.4/MIN (I), and 188.9/min (H); respiratory rate, 56.4/min (I), and 62.0/min (H); and VEBTPS, 145.2 1/min (I), and 143.3 1/min (H). It was concluded that the intensities of both treadmill methods, H and I, were sufficient to produce a nonsignificant difference in maximal VO2 values with the type subjects employed.