The World Health Organization is the global authority on health issues. Since its inception in 1948, it has made large strides in advancing its goal of the highest attainable level of health for all people. Through the years, the organization has faced many setbacks, but it has also marked numerous achievements. The global forces that necessitated its establishment continue to mold and influence the organization. This article discusses how the World Health Organization started, its functions, and what it is doing to maintain its relevance in the twenty-first century. This article also brings into focus the fight against tropical diseases.