* By a two-thirds vote of both houses of Congress, followed by ratification by three-fourths of the state legislatures. This is the most common method of amendment.
* By a national convention, called by Congress at the request of two-thirds of the state legislatures, followed by ratification by three-fourths of the state legislatures. This method has only been used once, in 1787, to adopt the Bill of Rights.
Article V also provides that the Constitution cannot be amended to abolish or alter the equal representation of states in the Senate without the consent of the affected states.