Officers in the borough attended the incident in Highlands Avenue after they were called at 4.31pm on Sunday, June 11.
Ealing Police warned the public that there may be delays in the area whilst they dealt with the "unexploded WW2 device".
On closer inspection, officers quickly found that there was nothing to be concerned about.
A spokesman for the Metropolitan Police said: "We were called to reports of unexploded ordinance found in the rear garden.
"On examination it was found not to be ordinance.
"There was a full stand down at 5.06pm."
The police would not confirm what the find was.
In April this year, an unexploded bomb was cleared away hours before the famous Oxford and Cambridge boat race .
In another incident in March, the navy carried out an explosion on a Second World War device found in Bondesbury Park .
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