Officers were quickly on the scene in Saltcoats after reports of an incident last night.
Emergency services were called to Sandylands Holiday Park in the Ayshire town at 11.35pm.
It is understood the 41-year-old man, who has not been named, was injured during a fight.
He was treated by paramedics but was pronounced dead at the holiday park in James Miller Crescent, shortly after they arrived.
Police today confirmed they are treating the death as suspicious and are trying to piece together exactly what happened.
Forensic teams spent several hours combing the holiday park and surrounding areas for evidence.
Specialist officers were at the scene last night carrying out preliminary inquiries.
Police cordoned off a large area around Auchenharvie Park shortly after 11.30pm, and a fleet of emergency service vehicles were at the scene.
A post-mortem examination will take place to establish the exact cause of death.
Officers today remained at the park, guarding the entrance to the crime scene.
Witnesses are being asked to come forward, but detectives are following a positive line of inquiry.
A Police Scotland spokeswoman said: "We received a report of a man injured following an altercation at Sandylands caravan park in Saltcoats at around 11.35pm.
"Emergency services attended and a 41-year-old male was pronounced dead at the scene.
"We are following a positive line of inquiry."
Anyone with any information is asked to contact Police Scotland on 101.