Objective: The least populated state of India, Sikkim is situated over 6,000 ft as of the sea level. The health of people residing at high altitude is shaped not only by the low-oxygen environment, but also by population ancestry and socio-cultural determinants. These factors may also have an influence over their physical fitness level. Thus the present survey work was designed in order to assess the influence of high altitude on physical fitness and anaerobic power. Material & Methods: The study was conducted in randomly selected young adult male residents of Gangtok, Sikkim (mean age 22.0) and the college students of Kolkata (mean age 21.9) served as controls. Some parameters of physical fitness and endurance were measured using resting heart rate, blood pressure, PFI, energy expenditure, VO2max etc. Results: A significant difference (p<0.05) in blood pressure, PFI, energy expenditure, BF% and anaerobic power were found in Sikkimese. Conclusion: This study implies health of young Sikkimese is not only under the influence of low-oxygen environment but also by their socio-cultural factors over their physical parameters.