Díaz, who graduated in Biology at the National University of Cordoba and specialises in botany, has focused on the role of biodiversity in countering climate change. The jury said her work was a "scientific reference in the area of ecology."
The duo's work "has placed them at the forefront of new lines of research with future important implications in the fight against climate change," the jury said in a statement.
The 50,000-euro (US$55,000) annual award is one of eight Asturias prizes handed out yearly by a foundation named for Crown Princess Leonor. Other categories include the arts and sport. Recipients also receive a sculpture by Joan Miró and a diploma.
Its far from the first award for either scientist. Chory has previously received prestigious awards including the L'Oreal-Unesco Award for Women in Science, while Díaz holds Platinum Konex prizes in biology and ecology.
Díaz is also an elected member of the National Academy of Sciences of the United States, the Academy of Sciences of France and the British Royal Society.