A torrential downpour in Buenos Aires left the Monumental pitch underwater, and the decision was taken to call off the game 45 minutes before the scheduled kick-off.
The match has been rescheduled for Friday at 9pm local time (midnight GMT).
The long-awaited Superclasico de las Americas had been put in jeopardy early on Thursday, with heavy rain lashing the Argentine capital for most of the day.
Both teams agreed to request postponement for the following day, and the decision was made official after a formal pitch inspection by the match officials.
Argentine FA vice-president Claudio 'Chiqui' Tapia earlier told reporters that there was a "99 percent chance" of the game being called off, even before both teams had arrived at the Monumental.