The purpose of this study was to investigate the 8-week of roller-ski aerobic high-intensity interval training on aerobic and anaerobic power in cross-country skiers. 10 male (age, 18.3 +/- 2.1 years; height, 171.3 +/- 4.12 cm; weight, 61.4 +/- 6.28 kg) and 8 female (age, 16.1 +/- 0.3 years; height, 158.3 +/- 6.47 cm; weight, 49.3 +/- 0.7 kg) junior cross-country skiers completed the study. All skiers performed 2x2-km all-out uphill intervals with roller-skis, 3 times a week, in addition to their traditional training program. Measurements included maximal oxygen consumption (VO2max), anaerobic power, and also for 2-km time-trial performance. All values were listed as pre-to post-test mean (+/- SD), significant level, and percentage changes (%). Pre-to post-testing changes in VO2max, anaerobic power, and also 2-km time-trial performance were significantly higher during all post-test trials in all groups (p<0.005). As a result, we suggest that the skiers should integrate the roller-ski aerobic high-intensity interval uphill models in their training programs for improving performance.