Bandaranayake was found guilty of not disclosing the details of 20 bank accounts and of purchasing a property and then taking judicial control of cases involving the company that sold it. She also was found to have a conflict of interest because she had supervisory powers over judges hearing a corruption case against her husband, a former state bank chairman.
She has said she was not given an opportunity to cross-examine her accusers and had insufficient time to prepare for her defense. She also said ruling party lawmakers at the inquiry hurled personal insults at her.
President Rajapaksa enjoys the support of more than two-thirds of the 225-member Parliament. Lawmakers voted 155 to 49 on Friday to impeach Bandaranayake. Twenty lawmakers, including four from the ruling party who disagreed with the impeachment, were absent.
The impeachment also drew international concern.
The United States Embassy in Colombo said it was deeply concerned by the proceedings.
"This impeachment calls into question issues about the separation of powers in Sri Lanka and the impact of its absence on democratic institutions," it said in a statement.
Sam Zarifi, Asia-Pacific director for the Geneva-based International Commission of Jurists, said the impeachment has "thrown into chaos the entire system of checks and balances in the country."
"As an immediate matter, this has precipitated a legal and constitutional crisis of unprecedented dimensions," he said in a statement.
Bandaranayake, who had long been viewed as pro-government, faced the allegations after she issued a ruling against a law promoted by a member of Rajapaksa's family.
The government is largely controlled by the Rajapaksas, including the president's older brother Chamal Rajapaksa, the speaker of Parliament. Two more brothers run the ministries of defense and economic development. One of the president's sons is a member of Parliament.