In this Spanish name, the first or paternal surname is Díaz and the second or maternal family name is Mancilla.
María del Carmen Díaz Mancilla (born July 15, 1970) is a retired long-distance runner from Mexico. She competed at the 1996 Summer Olympics in Atlanta, Georgia, where she finished in 33rd place in the women's marathon event. She set a personal best of 2:29:48 hours for the marathon in 1996.