Wearside had been experiencing heavy rain all day, and with water building up across sections of the pitch, officials have decided to postpone the game, which was scheduled for 3pm BST, until a later date.
Black Cats boss Martin O'Neill was seen with officials inspecting the pitch, who had been checking for much of the afternoon, but the decision was made just 20 minutes before kick-off to cancel the fixture.
The late decision will not go down well with Reading fans, who will now face a 302-mile trip back to Berkshire.
All other matches in the Premier League should go ahead as normal, and are not expected to be under any uncertainty, with Sunderland experiencing by far the worst weather of the day. The Premier League will announce the rescheduled date for the game in due course.