Police got a 911 call at 12:53 a.m. and when they arrived at Park Street west of Rustic Road they found the body of Michael Vanhulse of Centereach in the roadway.
He was pronounced dead at the scene by a physician assistant from the Office of the Suffolk County Medical Examiner.
Police are looking for witnesses to the accident and said Vanhulse's injuries "were consistent with him getting struck from behind by a motor vehicle."
Anyone with information can call Crime Stoppers at 800-220-8477 or Sixth Squad detectives at 631-854-8652. All calls will be kept confidential.