Around 10.30am on Wednesday (September 22), officers were called to assist the ambulance service who were attending to a man found injured in Lochside Road.
The 39-year-old had sustained serious head and spinal injuries and was taken to hospital, where he remains receiving treatment.
Enquiries are ongoing to establish how he came to suffer such injuries. Officers have carried out door-to-door enquiries and are reviewing available CCTV footage.
Anyone who may have seen the man is asked to contact police.
He was wearing blue shorts, blue trainers, a t-shirt and black puffer-style jacket, a black baseball cap and dark rimmed glasses.
Detective Sergeant Craig Semple from Ayr Police Station said: “This man was found with very serious injuries and we are investigating how he came to sustain these.
Those with information should contact Police Scotland on 101 and quote incident number 0901 of 22 September 2021.