Swansea Council has handed over operational control of the Stadium to the Premier League club Swansea City.
Swansea City will now pay annual rent to Swansea Council for the lease of the Liberty Stadium.
It's the first time the council will receive an annual income from the ground.
The club will also have to provide authorities with a share of any money from the stadium naming rights.
The new agreement means the Ospreys can continue playing at the stadium on a long-term lease.
The council-owned stadium, which was built in 2005, had been run by a tripartite agreement between the council, the Swans and the Ospreys - all of whom have representation through the mutually controlled Swansea Stadium Management Company (SSMC).
Swans majority shareholder Jason Levien says the agreement "begins a pathway to stadium expansion."
As part of the arrangement, the Swans have committed to funding the construction of two new 3G pitches in Swansea every five years for community use.