AbstractTo investigate a simplified Master's two‐step test (MTT) for preschool children aged 4 to 6 years exercise tests with new stairs, with risers 18 cm and 20 cm high, were employed. The subjects were 162 preschool children who were divided into four groups according to the height of the riser and the number of steps taken (60 and 72 steps per 3 minutes).In these tests, the 4‐year‐old children obtained similar mean heart rates immediately after exercise (156.9 to 161.6 BPM) in spite of different exercise tests, and the 5‐ and 6‐year‐old children obtained significantly higher mean heart rates (166.0 and 162.1 BPM, respectively) in the test with a 20 cm riser taking 72 steps. If a single protocol is to be used for children aged 4 to 6, the test with a 20 cm riser and taking 72 steps seems to be the best with reference to the achieved heart rates and perform