PCOM was established on January 24, 1899 as the Philadelphia College and Infirmary of Osteopathy (PCIO). It was the third osteopathic medical school to open in the United States. In September 1899, the first PCIO degree was awarded, and in February 1900, the first PCIO "class," comprising one woman and one MD, graduated. In May 1921, PCIO was renamed to Philadelphia College of Osteopathy (PCO). In 1967, the school adopted its present-day name, becoming the Philadelphia College of Osteopathic Medicine (PCOM).