The torrential rain which has covered much of England has led to the rare occurrence of a match being called off because of it in the summer.
A Sunderland club statement said: "Torrential rain across Wearside overnight and throughout Saturday in the build up to the game led to an inspection from Match Officials.
"Despite attempts from club staff and the officials to get the game to go ahead, the postponement was announced by referee Neil Swarbrick after thorough checks on the Stadium of Light pitch.
"An announcement for the rearranged fixture will be made in due course and all tickets purchased will still be valid."
Sunderland were expected to give new striker Steven Fletcher a debut following his £14 million move from Wolverhampton Wanderers on Friday.
Another new addition to the club's ranks, Adam Johnson, was scheduled to be welcomed by the club's fans after he also completed his £11 million move from Manchester City on Friday, but did not do so in time to be eligible for the match.
The Black Cats were hoping to build on last weekend's creditable 0-0 draw at Arsenal, while newly-promoted Reading were looking for their first win back in the top flight after drawing with Stoke City on the opening day and then losing 4-2 at Chelsea on Wednesday.