Airbnb, McDonald's, Nike and BuzzFeed are testing full-screen ads.
Instagram's five-month-old Stories brings 150 million active users to the platform daily.
Now, the social media network is giving advertisers a way to reach them.
On Wednesday, Instagram said it was introducing advertising within the ephemeral image-sharing feature and metrics to measure its effectiveness.
The Facebook-owned app said it is partnering with more than 30 companies to test advertising in Stories in the US, including Airbnb, McDonald's, BuzzFeed, Nike, L'Oreal, General Motors, AT, Coca-Cola and Live Nation.
The option will become available globally in the coming weeks.