The superhero team-up will reach $600 million at the domestic box office today, its studio announced.
The Avengers joins Cameron's Avatar and Titanic as the only films to achieve that milestone.
The Iron Man-and-friends adventure, which opened May 4, kicking off, then dominating the summer movie season, will hit the mark in its 54th day in theaters.
It is the second-fastest to $600 million, behind Avatar (47 days) and ahead of the marathon runner that was Titanic (252 days).
At $600 million and change, The Avengers sits in third place on the list of Hollywood's all-time domestic champs.
The Avengers is also the third-biggest grossing film of all-time worldwide, with an overall haul north of $1.44 billion.
It obviously has outgrossed every Marvel-superhero movie, and has outdone the combined domestic takes of The Incredible Hulk, Captain America: The First Avenger and Thor, three of the films leading into the Joss Whedon-directed mash-up.