The aim of this research was to analyze physical and chemical characteristics of high altitude lakes (Gokyo lake series, Imja lake, Pyramid lake) of the Sagarmatha National Park, Khumbu region located above 4500 m altitude. The lake water was studied for three years (2008, 2009 and 2010) to compare the annual changes in the parameters. The findings created a database for present status of high land lakes of Nepal, which can be used for the management of lakes as well as to study the impact of tourism on water quality. The lake water quality in general still stands good in terms of standards for drinking water (WHO, Nepal standard) but degradation process has started. Total nitrogen in water samples was lower than the WHO standard but an increase in the nitrate nitrogen has been recorded. Similarly, total phosphorrous quality was also found increased.