The FIA made its decision to reinstate the Bahrain Grand Prix to the F1 calendar after a report revealed the country's situation has "stabilised".
The president of the sport's world governing body Jean Todt told the BBC the FIA voted unanimously after advice from vice-president Carlos Gracia.
"Our special envoy had many meetings in Bahrain, even with the human rights people responsible," said Todt.
"He found a stable situation, a quiet one, and we unanimously agreed."
The race, originally due to be held on 13 March, was called off in February because of pro-democracy protests in which more than 20 people died and will now be held on 30 October.
Todt added: "Carlos's report was discussed by the World Council and the decision was taken to accept to re-programme the Bahrain Grand Prix in 2011.
"We got a request from the opposition to the government to run the event and Carlos met with many people, including those working on the circuit, those in all the suburbs of the capital, and the report came back after that.
"The messages coming out are about peace, about restoring a good situation in this part of the world. Lots of other authorities have been encouraging [things] to go back to normal. My thinking is that, as a sporting body, we must support that."
However Avaaz, an international campaigning organisation, issued a statement in which they contradicted the FIA's findings.
"Claims that calm has been restored and life is back to normal in Bahrain are completely untrue," said campaign director Alex Wilks. "In the last week the police have continued to use tear gas, rubber bullets and sound grenades to break up peaceful marches, killing and injuring dozens of people."
The BBC's F1 reporter Ted Kravitz said that FIA president Todt has given himself a get-out clause to cancel the race if the security situation in Bahrain deteriorates over the coming months.
Todt said that the situation in the Gulf Kingdom would be monitored ahead of the scheduled race. "If we have clear evidence that there is a risky situation this will obviously be taken into consideration," he said.
The FIA said the unanimous decision to put the race back on "reflects the spirit of reconciliation in Bahrain".
A state of emergency in Bahrain was lifted on 1 June, but there have been reports of further violence in the capital Manama on the day of the decision.
Wilks added: "On Monday, 47 Bahraini doctors and nurses who simply provided treatment to injured protesters have been charged by a military court with attempting to topple the kingdom's monarchy.
"Whitewashing these abuses is an insult to the hundreds of protesters jailed and dozens killed in their struggle for change. The FIA's decision to go ahead with the race based on one blinkered account of the situation shows how money has prevailed over morals.
"The main organisation that has provided this information, the Bahrain-based National Institute of Human Rights, is closely associated with the Bahraini Government and it appears the FIA investigator failed to contact any of the other key human rights organisations on the ground.
"Now it is up to the teams to stand up for what is right and boycott the race."
Red Bull driver Mark Webber remains uncertain that the rescheduled race will take place. The Australian, 34, wrote on his official website: "Even though a decision has been made, I'll be highly surprised if the Bahrain Grand Prix goes ahead this year.
"As a competitor I do not feel at all comfortable going there to compete in an event when, despite reassurances to the contrary, it seems inevitable that it will cause more tension for the people of that country."
Todt, however, dismissed Webber's comments as personal opinion rather than a reflection of the F1 field as a whole.
The Formula One Teams Association (Fota), which groups all the teams except Hispania, said it was assessing the situation.
"That (FIA) decision is likely to be discussed internally within Fota, and a more detailed joint position may be defined after those discussions have taken place," it said.
However, Fota vice-president and Ferrari team boss Stefano Domenicali - who also has a seat on the world council - is understood to have voted in favour of restoring Bahrain to the 2011 calendar.
Force India owner Vijay Mallya is also believed to have voted in favour of a return to Bahrain.