Chinchilla was born in Carmen Central, San José in 1959. Her father was Rafael Ángel Chinchilla Fallas. He was a former comptroller of Costa Rica. Her mother was Emilce Miranda Castillo. She married Mario Alberto Madrigal Díaz on 23 January 1982 and divorced on 22 May 1985. She had a son in 1996 with José María Rico Cueto, a Spanish lawyer who has a Canadian citizenship; Chinchilla married him on 26 March 2000. He died in April 2019, aged 84.