Which award in mathematics is considered to be the equivalent prize for Nobel Prize?

The Fields Medal is considered to be the equivalent of the Nobel prize for mathematics. John Charles Fields (1863-1932), a Canadian mathematician, endowed funds in his will for an award for mathematical achievement and promise that would emphasize the international character of the mathematical endeavor. The first Fields Medal was awarded at the International Congress of Mathematics meeting in Oslo in 1936. Since 1950 the medal has been awarded every four years at the International Mathematical Congress to between 2 and 4 mathematicians. Although there is no specific age restriction in Fields' will, he did wish that the awards recognize both existing work and the promise of future achievement, so the medals have been restricted to mathematicians under the age of 40. No woman mathematician has ever won a Fields Medal.

Reference:

  1. IMU Awards and Prizes, [contains complete list of all winners of the Fields Medal and pictures of the front and back of the medal]
  2. Historical Introduction by Alex Lopez-Ortiz, part of his FAQ site on mathematics.