Amid a barrage of criticism over its legislation banning what it dubs homosexual propaganda, Russia responded to IOC calls to ensure that the law will not undermine the Games in the resort of Sochi.
"The International Olympic Committee has today received strong written reassurances from the Russian government that everyone will be welcome at the Games in Sochi regardless of their sexual orientation," the IOC said in a statement.
It quoted Dmitry Kozak, the deputy prime minister in charge of Russia's hosting of the Olympics, as saying that the country "guarantees the fulfilment of its obligations before the International Olympic Committee in its entirety."
Kozak said that Russia had "committed itself to comply strictly" with the Olympic Charter.
The charter, which sets out the rules and principles of the Olympic movement, bans "any form of discrimination with regard to a country or a person on grounds of race, religion, politics, gender or otherwise".
In June, Russian president Vladimir Putin signed a law punishing the dissemination of information about homosexuality to minors.
Activists say it can be used for a broad crackdown against gays and there are fears it could be used against athletes and others in Sochi.
It has sparked calls for a boycott in some quarters and Russian officials have said all athletes will have to obey the law at the Games.
"The IOC is clear that sport is a human right and should be available to all regardless of race, sex or sexual orientation," the Olympic body said.
"The Games themselves should be open to all, free of discrimination, and that applies to spectators, officials, media and of course athletes," the IOC said.
"We would oppose in the strongest terms any move that would jeopardise this principle."