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.
During the American Civil War, he was medical director of the New York Volunteer Hospital, treating wounded soldiers from the Union army. He was prominent in the United States Sanitary Commission, which administered supplies and medical assistance to the field armies.
After the war, he assisted in establishing the Columbia School of Mines in 1864. he then founded the Brooklyn Eye and Ear Hospital in 1868 and the Manhattan Eye and Ear Hospital in 1869. He served as a professor of diseases of the eye and ear through 1888, when he died in New York City.
- Who Was Who in America: Historical Volume, 1607-1896. Chicago: Marquis Who's Who, 1963.