The Millennium Prize Problems are seven problems in mathematics that were stated by the Clay Mathematics Institute in 2000. The problems are:

• Birch and Swinnerton-Dyer conjecture

• Hodge conjecture

• Navier–Stokes existence and smoothness

• P versus NP problem

• Poincaré conjecture

• Riemann hypothesis, and

• Yang–Mills existence and mass gap.

A correct solution to any of the problems results in a US $1M prize (sometimes called a Millennium Prize) being awarded by the institute. The only solved problem is the Poincaré conjecture, which was solved by Grigori Perelman in 2003.