Facebook launched Marketplace to allow people to buy and sell items locally as the social media network tries new ways to keep users engaged.
The feature will appear as a "shop" icon at the bottom of the Facebook app and will allow users to list or search for items on sale in their neighborhood.
The company will not facilitate the payment or delivery of items and will not take a cut from any transactions, Facebook said.
The new service will be rolled out in the United States, the U.K., Australia and New Zealand for iPhone and Android users over the next few days, the company said in a blog post, adding that the feature will be available on the desktop version in the coming months.
More than 450 million people already visit Facebook groups that have items to buy and sell each month, the company said.
Last year, Facebook said it was testing several ad features that allow users to shop directly through its app, an effort to move further into e-commerce.
Facebook's shares were little changed at $128.39 in morning trading on Monday on the Nasdaq.