Issued by the United States, this 5-cent commemorative stamp honors pioneering physicians Dr. William J. Mayo and Dr. Charles H. Mayo, founders of the renowned Mayo Clinic. The finely engraved green design depicts the two medical innovators in profile, symbolizing their lasting contributions to modern medicine and cooperative healthcare practice. Released in the 1960s commemorative series celebrating distinguished Americans, the stamp is a respected thematic item for both medical and U.S. commemorative collectors. Its classic portrait layout and historical significance make it a desirable addition to health-themed and professional-achievement collections.