Tens of thousands of flag-waving demonstrators took to the streets of the capital to protest a Nov. 2 election that the United States has declared a "massive fraud."
Shevardnadze, speaking live on Georgian television, said, "I realized that what is happening may end with spilled blood if I use my rights… I have never betrayed my people and I decided that I should resign."
Asked where he was going to live, Shevardnadze said, "At home."
News of the resignation sparked roars, cheers and excited dancing among the tens of thousands of opposition supporters gathered outside the parliament building, which had been seized by demonstrators the day before.
Russia and the United States both fear instability in the ex-Soviet republic, strategically located on the borders of Russia and Turkey, between the oil-rich Caspian Sea and the ports of the Black Sea. Russia has military units stationed in Georgia. U.S. troops are also in the country on a counter-terrorism mission, training Georgian forces to uproot Islamic insurgents from neighboring Chechnya who take refuge in Georgia's mountainous terrain.
The roots of the current upheaval lie in the deep economic misery of most of the population and the rampant corruption that has characterized Shevardnadze's reign. Respected outside of Georgia for his role in helping to end the Cold War as foreign minister under Mikhail Gorbachev, the 75-year-old Shevardnadze is considered a disappointing relic at home.
CBS News Correspondent Tom Fenton says Shevardnadze is now considered "damaged goods" in the West.
As the protests built over the past two weeks, Shevardnadze's grip on the government loosened and even his top security aide acknowledged that the election had been fraudulent. On Saturday, hundreds of demonstrators swept through parliament minutes after Shevardnadze began his speech before the first meeting of the delegates elected on Nov. 2.
Shevardnadze remained defiant, pledging "I will not resign" even as he was whisked away by bodyguards.