Customers can get their choice of a Chick-fil-A chicken biscuit, a three-count Chick-n-Minis order, or an Egg White Grill free of charge until September 30.
Customers must have the Chick-fil-A app to get the free food. The offer will show up on their home screen under "available treats."
Customers without the app can also get free breakfast, but they have to download it by September 10.
This is the second time Chick-fil-A has offered free food nationwide to promote its app.
The restaurant chain offered free sandwiches in June.
Going forward, Chick-fil-A plans to offer even more free food through its app.
The app has a built-in rewards program that will send customers free-food offers based on what they typically order.
When customers get free treats from Chick-fil-A, they will have the opportunity to rate them. Those ratings will be factored into the app's future free-food offers.
Customers will typically get a choice of several items for their free-food offers. For example, they will be allowed to choose among a free drink, dessert, or medium fry.