The online mode and associated apps are up and running after recent trade pile issues.
"Maintenance is now over! Get back on the pitch!," the firm tweeted.
Original Story: FIFA 13's Ultimate Team has been taken offline by Electronic Arts.
The online trading mode and associated apps have been removed while the development team deals with trade pile issues.
The decision to remove the mode comes after users complained of missing cards and the inability to add traded players to their teams.
Electronic Arts is yet to offer a time-frame for the fix, although a recent statement suggests that the problem might take days to solve.
"FUT13 is temporarily down until further notice while we address the trade pile issue," reads a statement by Electronic Arts.
"This is to ensure that more users do not become affected and an optimal experience can be sustained in the future.
"We'll keep you updated as soon as we have additional information throughout the coming days. Other FIFA 13 online game modes will not be affected.
"Thanks for your patience and sorry for the inconvenience," the statement concludes.
> Digital Spy's 'FIFA 13' review: 'Another trophy-winning instalment from EA'
Copyright: EAFIFA sold more than 4.5 million copies across all platforms in its first five days at retail - making it not only the UK's biggest game launch of 2012, but also the biggest sports game launch ever.
It dominated the all-format charts after its first weekend, selling over 1.23m copies in its first 48 hours, and was recently revealed to have topped 7.4m sales in four weeks.
FIFA 13 is available on Xbox 360, PS3, PC, Wii, PSP, 3DS, PS2, Vita, iPhone and iPad. A Wii U version will be released alongside the launch of the console.
Watch the FIFA 13 Wii U gameplay trailer below: