The purpose of this study was to examine and compare the physiological responses of two different types of bouldering activities in upper elementary school students. As part of a physical education fitness unit, fourth and fifth grade students (N = 64) from two Midwestern elementary schools participated in two different activities at the gymnasium bouldering wall: (1) Traditional bouldering without any specific instruction from the teacher; and (2) a structured bouldering game. Paired-samples t-tests were performed on students' heart rate (HR) data to measure for significant differences in resting and HRs for both bouldering activities and to compare active HRs of the two activities. Significant differences (p less than 0.05) occurred between active and resting HRs for both activities, while no significant difference in mean active HRs occurred between the two activities. Results indicate that bouldering is a legitimate physical fitness activity for elementary school students regardless of the method used. (Contains 3 tables and 1 figure.)