A man in his 40s was seriously injured in an early morning collision on the outskirts of Llangefni.
Police say he was hit by a blue Ford Fusion car on the B4422 at Rhostrehwfa at just before 1.15am on Sunday morning.
The local man was taken to Ysbyty Gwynedd in Bangor, but he was later transferred by air ambulance to a specialist unit at the Royal Stoke University Hospital.
His injuries were described as serious and potentially life-threatening.
An investigation is continuing and North Wales Police are appealing for any witnesses to come forward.
Detective Sergeant Katie Davies of the Serious Collisions Investigation Unit said: "Our enquiries to establish what happened are underway and we are making a renewed appeal for anyone who witnessed the incident or who may have information to please get in touch with us."
"Any little bit of information could be vital in helping is piece together what happened."
Anyone with information should contact North Wales Police on 101, or use the live web chat, quoting reference no. Q162262.