Diego Álvarez Chanca (year of birth and death unknown) was a Spanish physician and companion of Christopher Columbus.
Chanca was a physician-in-ordinary to Ferdinand and Isabella, which is how he was introduced to Columbus. He was appointed by the Crown of Spain to accompany Columbus' second expedition to America in 1493. Shortly after landing on Hispaniola, Columbus suffered from an attack of malarial fever, which Chanca successfully treated. Several other members of the crew were also treated for malaria during this period.
Chanca's opinion was also sought when Columbus was selecting a site for his first settlement, Isabella. While there, Chanca wrote a letter to the municipal council of his native city of Seville, which was the first document describing the flora, the fauna, the ethnology, and the ethnography of America.
After his return to Spain in February 1494, he published in 1506 a medical treatise entitled Para curar el mal de Costado (The Treatment of Pleurisy), and in 1514, he published a work in Latin criticizing a book entitled De conservanda juventute et retardanda senectute, the work of Arnaldo de Villanova, a brother-physician.