It means the Leone Stars will now play their Group 4 home qualifiers against Nigeria, South Africa and Equatorial Guinea in Freetown.
The National Stadium in Freetown passed a final inspection by Zambia's Kalusha Bwalya on behalf of football's world governing body.
Fifa has also warned the Sierra Leone Football Association (SLFA) that refurbishment work on the stadium must be completed in time for the World Cup second round matches in November.
Bwalya told BBC Sport that: "Personally I'm impressed with the refurbishments work so far at the stadium and I think a good job has been done."
The stadium was banned in March because of poor dressing rooms and sub-standard pitch among other things.
The Leone Stars are due to play their first home game against Nigeria on 7 June, a week after their first match in the qualifiers against Equatorial Guinea in Malabo.
The DR Congo will be able to host their home matches in the first phase of Group 12 of the qualifiers against Egypt, Malawi and Djibouti.
Like Sierra Leone, the stadium in Kinshasa is still subject to further inspections.
The president of the DR Congo football association, Constant Omari Selemani, was delighted that the stadium in Kinshasa has been given the go-ahead to host games.
"Fifa will see that all the refurbishment works that were inspected a few days ago will be finished by the end of the first round of qualifiers," Selemani said.
"All parties involved should speed up work on the stadium so that those inspectors find that we are ready.
"We should not slow down the works in the stadium after getting this news from Fifa."
Fifa has already given the go-ahead for 2010 qualifiers to be played at the Konkola Stadium in Zambia and Independence Stadium in Namibia.