It happened Sunday on Sunrise Highway in Bohemia.
Police say a private ambulance was traveling north on Oakdale-Bohemia Road when the ambulance and a Suburban traveling westbound on Sunrise Highway Service Road crashed at the intersection at approximately 5:50 p.m.
The Suburban overturned and struck a sedan traveling southbound on Oakdale-Bohemia Road.
Two people in the Suburban and two people in the ambulance were transported to Southside Hospital for non-life-threatening injuries.
The two people in the ambulance are employees of the ambulance company. They suffered head and back injuries.
There was no patient in the ambulance at the time.