Charles Horace Mayo

Charles Horace Mayo (July 19, 1865 – May 26, 1939) was an American medical practitioner and a co-founder of the Mayo Clinic.

Mayo graduated from the medical school of Northwestern University (now called the Feinberg School of Medicine) in 1888 and joined his father, William Worrall Mayo, and older brother, William James Mayo, in their medical practice in Rochester, Minnesota. In 1889, the Mayos opened the first general hospital in southeastern Minnesota and pioneered the principle of "group practice". The Mayo Clinic came to be regarded as one of the foremost medical treatment and research institutions in the world. Within Mayo's lifetime it registered one million patients.

As far as he could within a general practice, Mayo specialized in surgery of the thyroid and nervous system. He was also responsible for the clinic's ophthalmic patients until 1908. In the face of his father's resistance, he and his brother insisted on sterile conditions in the operating room. He was also an early adopter of X-rays as a diagnostic tool.

Mayo retired in 1928 and died in 1939 in Chicago, Illinois. He is buried near his parents and brother at Oakwood Cemetery in Rochester. His son Charles William Mayo continued his work at Mayo Clinic.

The United States Postal Service printed a stamp depicting him and his brother on September 11, 1964.