Police and ambulance were called to E4 at the height of Märsta, in the direction of Arlanda, early Sunday morning.
Five cars had collided with each other.
Two people have been taken to hospital by ambulance and some of the cars will need to be recovered from the accident scene.
The Swedish Transport Administration states that there is very limited access until at least 8am.
According to the police, it is “extremely slippery” at the scene.