It's thought the report will say there's no evidence of the weapons of mass destruction which US president George Bush says Saddam Hussein has.
But it's thought it'll also say Saddam hasn't been honest about everything that is there.
Different governments will talk about the report on Wednesday.
Then on 31 January George Bush and British Prime Minister Tony Blair will talk with each other.
After that, there'll be another report on 27 March.
In the meantime, the US and UK say if Saddam doesn't help with more information, Iraq could be attacked.