A company statement said additional time was needed for "complementary verifications" on the Ariane 5 ES rocket that will take the craft aloft.
A new launch date is expected to be announced next week.
The Automated Transfer Vehicle (ATV) dubbed "Georges Lemaitre" is the last of five supply vessels Europe was scheduled to provide to the ISS.
Like its predecessors, the freighter will blast off from Kourou, French Guiana.
The size of a double-decker bus, the cylindrical ATV modules are launched by a heavy Ariane 5 ES rocket, after which they use on board motors and starlight navigation to rendezvous and dock with the ISS.
At the end of a mission usually lasting several months, they undock from the ISS and burn up in the atmosphere in a controlled de-orbit.
The fifth ship, which will carry the heaviest cargo yet with over 2.6 tonnes (6,700 pounds) of dry goods, 850 litres of potable water and three tonnes of fuel, is named after the Belgian cosmologist who fathered the concept of the Big Bang that created the Universe.
After the last ATV flight, the ISS will be resupplied by Russia's Progress freighter and fledgling US private contractors.
