The Republican firebrand was supposed to pose for a picture with Mr Macri and other world leaders but walked off the stage. Hilarious footage shows Mr Trump shaking hands with the Argentinian President before he wandered off. Mr Macri looked sheepish and perplexed after President Trump deserted him.
An aide could be seen chasing the billionaire as he strolled off the stage.
Mr Trump was later heard saying “get me out of here” off camera.
He eventually returned to the stage and stood in the middle of the world leaders to pose for a photo.
The embarrassing incident in Buenos Aires was the second gaffe for Mr Trump during the G20 summit.
Earlier Friday, the President stood side by side with the South American president and appeared to struggle to understand the translation delivered into his earpiece.
Mr Macri shared greetings with the US President in Spanish.
He said: “It’s a great opportunity to thank you.
“To thank you for the huge support we have received from the United States and from your government, especially during this past year.
“We’ve been going through some difficult times.”
Mr Trump threw his translation earpiece to the ground telling Mr Macri: “I think I understood you better in your language than I did on this.
“But that’s okay”.
Donald Trump has a history of embarrassing gaffes where he wanders off.
During a visit to Israel in May 2017, the US leader began walking out of from a photo with Prime Minister Benjamin Netanyahu.
Appearing lost, Mr Trump had to be ushered back towards the Israeli Prime Minister.
Two months later, Mr Trump gave a speech in Warsaw, Poland.
After speaking, he was seen walking aimlessly around the stage, appearing unsure of where to go.