World Health Organization (WHO) is a multinational health association which is established by the United Nations. It is a multinational association working in all countries of the world. It was founded after end of World War in 1948. Primary function of it is generating global awareness about public health. It has successfully eliminated some of the epidemics in the world like smallpox. It is operating against HIV Aids, life-threatening fevers and tuberculosis. Constitution of World Health Organization is a universal law which is implemented throughout the world. World Health Day is the primary event of WHO which is celebrated throughout the world.