Cornelius Rea Agnew (August 8, 1830 – April 18, 1888) was an American physician. Agnew was born in New York City, the son of William Agnew and Elizabeth Thompson Agnew. He graduated from Columbia College in 1849, and from the Columbia University College of Physicians and Surgeons in 1852. That same year, he was appointed surgeon-general of New York State. He began to practice medicine in 1854, and served as a surgeon at the Ear and Eye Infirmary in New York City from 1855 through 1864. In 1856, he married Mary Nash. His papers were donated to the National Library of Medicine in the late 1980s.