A 43-year-old man suffered serious head injuries when he lost control of his motorcycle in Lattingtown late Monday, Nassau County police said.
Police have not released the identity of the man, who was taken to a hospital in serious condition.
The crash occurred on Lattingtown Road near Winding Way at 10:37 p.m., police said.
Police said that first-responders, including Second Precinct officers, Nassau ambulance medical technicians and members of the Locust Valley Fire Department, performed CPR on the victim before he was transported.
An investigation into the cause of the crash is ongoing.
No criminality is suspected, police said.