The southbound carriageway of the A11 is closed following a collision near Barton Mills.
Suffolk police, East of England Ambulance and the fire and rescue service attended the scene.
Two cars and a motorcycle were involved with the collision.
The southbound carriageway is currently closed between Barton Mills and Red Lodge.
Police were called to the scene at 5.40pm while three fire engines responded to a call at 5.43pm, from Ely, Mildenhall and Newmarket.
The road closure and diversions is expected to remain in place for a number of hours.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here