The queen arrived in a glittering horse-drawn carriage wearing a crown studded with 2,000 diamonds. The ceremony included cannon fire, yeoman guards and mounted cavalry.
The queen gave a speech outlining the legislative plans of Britain's new coalition government. This is the first time the nation has had a coalition government since World War II.
Party leaders have made plans to reduce Britain's record $233 billion budget deficit and revive the economy.
"My lords and members of the House of Commons, my government's legislative program will be based upon the principles of freedom, fairness, and responsibility," the queen said.
The 84-year-old queen also announced plans to travel to New York in July to visit the United Nations.
