Bogus police officers targeted a house in Golborne after talking their way inside.
One distracted the occupant while the other went upstairs and stole property.
The force has since issued a warning about the offenders, who were in fake uniforms.
Residents should ask to see identification if anyone attends their address claiming to be a police officer.
For police, the ID should contain a picture and a blue background, whereas for police support staff the background is green.
In a post, GMP Leigh, Atherton and Hindley said: “Beware of bogus police.
“Golborne offenders, claiming to be police officers, have talked their way in to an address and whilst one distracts the occupant the other(s) have gone upstairs and stolen property.
“If anybody attends at your address claiming to be a police officer make sure you ask to see their identification - it should contain a picture and have a blue background; police support staff have a green background.
“If you are not happy do not let them in. You can make further checks via the 101 police line.”
