After two rounds of voting at the UN General Assembly, the two vacant East European seats went to Bosnia-Herzegovina and Slovenia.
Rights groups had strongly criticized Belarus's human rights record before the vote.
Bosnia had put in its bid at the last minute after Western countries reportedly persuaded it to enter the contest to spoil the bid by Minsk.
"I was particularly heartened by the election of Bosnia," U.S. Ambassador Zalmay Khalilzad, current president of the UN Security Council, told reporters after the vote. "We were particularly concerned about [Belarus's bid]. Some have called it the last dictatorship in Europe. To have Bosnia be elected, beside Slovenia, given the background of Bosnia in particular, is heartening. This was the right decision for the General Assembly."
The UN Human Rights Council was created in March 2006 to replace the UN Human Rights Commission.
The commission had been discredited because some countries with poor rights records had used their membership to protect one another from condemnation.
But the council has also come in for criticism, most recently when it decided in March to end scrutiny of Iran and Uzbekistan.
(with agency material)