The chairman of the Republican-led panel, Wisconsin Sen. Ron Johnson, has repeatedly insisted the investigation is not designed to hurt Biden, the presumptive Democratic nominee in this year's presidential election.
Another Republican on the committee, Florida Sen. Rick Scott, said at the vote that "we need to get to the truth about the Bidens' relationship with Burisma. These hearings will provide the Senate with the full picture."
A Biden campaign spokesman said in a statement that Johnson was "running a political errand" for Trump.
Democrats decried the investigations as politically motivated and said they are a distraction from work the committee could be doing to try to help mitigate the pandemic.
Senate Democratic leader Chuck Schumer accused Republicans of promoting "conspiracy theories."
"It appears the subpoena is just for show, a way to create the false impression of wrongdoing," Schumer said Wednesday from the Senate floor. "It's like in a third world dictatorship, a show trial with no basis in fact, with no due process, with no reality."
President Donald Trump was acquitted on Feb. 5, 2020, in the nation's third impeachment trial in history. After a 14-day Senate trial, Trump was found not guilty of charges of high crimes and misdemeanors. House Democrats passed two articles of impeachment against the president in December 2019. They charged Trump with abuse of power and obstruction of Congress. On the first charge, GOP Sen. Mitt Romney joined Democrats in a vote of 52-48, far short of the required two-thirds to convict. On the second vo
The president's efforts to have Ukraine investigate Hunter Biden's role as a board member for Burisma were at the heart of House Democrats' impeachment probe last year. Trump asked Ukrainian President Volodymyr Zelenskiy to investigate the Bidens on a July phone call that was later revealed by a whistleblower's complaint.
The House impeached Trump in December for pressuring the Ukrainian government on investigations while withholding military aid to the country. The Senate acquitted him in February.
The Associated Press contributed to this report.