The resources available to the Pan American Sanitary Bureau at its outset are meager at best: a budget of US$5000, borrowed staff and no permanent posts, not even a headquarters building. The first registered salary, that of an "executive clerk," appears in the Bureau's 1921 budget, which by then has quadrupled to US$20,000. Still, the staff remains small, and "travelling representatives" perform most of the Bureau's work throughout the 1920s. Successive directors appeal to successive meetings of the Organization's governing bodies for budget increases to enable the Secretariat to enhance cooperation with the countries in efforts to meet their health needs.

The positive response to those appeals and the return on the countries' increasing investments do not go unnoticed. In 1933, then director Dr. Hugh S. Cumming, claims that: "Fourteen years ago, the Pan American Sanitary Bureau existed in name only. Today its influence is felt not only in the countries of the Americas but throughout Europe." For his part, the president of the United States, John F. Kennedy, echoes the sentiments of other heads of state in 1962 in celebrating an earlier anniversary of the Organization: "Throughout the 60 years since its founding here in Washington, the Pan American Health Organization has served the health of the people of our hemisphere. Thanks to its vigorous leadership and the active cooperation of the 21 American Republics, many millions of Americans have been protected against malaria, yellow fever, smallpox, and other scourges of mankind. Today, it is a pleasure for me to salute your distinguished past as the world's oldest international health organization and to wish you every success in your continuing efforts to build a healthier hemisphere."

The history of the Organization is one of adjustment to the times. Given the subsequent explosion of information technology, for instance, the prediction in 1969 of then director Abraham Horwitz that "computers would surely have some role to play in health administration in the Americas" proves prescient. He then establishes at PAHO's headquarters a special section "charged with promoting computer science throughout the Region as well as with supportive functions for both the technical and the administrative activities of the Organization itself."

Today, a zeal for recruiting outstanding personnel, streamlining operations, and maximizing cost benefits has earned the Bureau a reputation as one of the most efficient of international bureaucracies at the effective service of member countries.