Police, firefighters and ambulances were called to Shepherds Bush at about 10.40am and roads surrounding the shopping centre were cordoned off.
Offices and residential buildings were also evacuated following the discovery of the unexploded bomb at a building site in Ariel Way, White City.
Due to an unexploded WW2 shell found today north of the centre, we have closed Westfield White City until further notice.— Westfield London (@westfieldlondon) July 8, 2015
Rest of the day off work thanks to a bomb found at Westfield! pic.twitter.com/ifyk4tH7fG— Henry Clark (@HenryDClark) July 8, 2015
They've just found a WW2 bomb in/nearby Westfield. Shepherd's Bush station a nightmare pic.twitter.com/7HlFxiDNLg— Alex Ferguson (@viewfromamerica) July 8, 2015
It is believed that the bomb was dropped during the Second World War.
The bomb has been found on a building site and is believed to have been dropped during the war— HammFul MPS (@MPSHammFul) July 8, 2015
Train services were suspended between Hammersmith and Edgware Road due to the "security alert".
Passengers were unable to gain access to Shepherds Bush Market Station and roads near the shopping centre were "chaotic" as a 400-metre exclusion zone was set up around the centre's perimeter.
It is believed that the unexploded bomb was found at the Westfield London Phase Two site, which is being developed next to the current shopping centre.
The Westfield addition is a £1billion project expected to generate 1,400 new homes, as well as retail space.
Specialist officers removed the suspected bomb at 12.40pm for examination and roads and the shopping centre opened shortly after.