Background:In altitude training for elite athletes, altitudes below 1700 m are generally known to have low physiological stimulation and training effects. Therefore, the purpose of this study is to investigate the effect of live high train high (LHTH) altitude training at an altitude of 1600 m on athletic performance, complete blood count (CBC), and erythropoietin (EPO) in cross-country skiers. Methods: In this study, South Korean Six male cross-country skiers participated. Exercise performance, CBC, and EPO were measured 3 days before altitude training and 4 days after the end of altitude training. The training program in this study was the LHTH altitude training method, and the polarized (POL) training program was applied. For exercise performance analysis the Bruce protocol was applied using a treadmill and gas analyzer. Blood variables CBC (red blood cell; RBC, white blood cell; WBC, hemoglobin; Hb, hematocrit; Hct, platelets) and EPO were measured at rest and immediately after exercise. Results: The effect of 3 weeks of LHTH altitude training on male cross-country skiers was as follows. There were no differences in body weight, muscle mass, body fat mass, or body fat percentage (p > 0.05). Although maximal oxygen uptake (VO2max) increased (p < 0.05), there was no significant difference in exercise time and maximum heart rate (HRmax) (p > 0.05). The heart rate measured at 2 minutes after the end of exercise decreased rapidly (p < 0.05). At rest, RBC, Hb, and Hct were increased (p < 0.001), but there was no significant difference between WBC and platelets (p > 0.05). Immediately after exercise, there was no significant difference in RBC and Hb (p > 0.05), but WBC (p < 0.001), platelets (p < 0.01), and Hct (p < 0.05) were significantly decreased. EPO was significantly decreased after training compared to before altitude training at rest and immediately after exercise (p < 0.001). Conclusions: The results of this study suggested that 3 weeks of LHTH training at an altitude of 1600 m could stimulate RBC, Hb, and Hct. Also, improved VO2max and recovery capacity along with increases in RBC and Hb mean that LHTH training at an altitude of 1600 m could induce a positive effect on physiological and performance changes in male cross-country skiers. We did not have a control group, and we do admit some limitations, including height adjustment, length of altitude training, and training program (intensity and volume). Nevertheless, LHTH training at an altitude of 1600 m can be a desirable intervention program when planning short-term altitude training for technical and physiological improvement in male cross-country skiers. In addition, it is suggested that exercise and living at high altitude stimulate blood variables and cardiopulmonary function, which will have a positive effect on exercise performance and health promotion not only for athletes but also for men in general.