Fellow officers, officials and friends and families of those fallen officers have been invited to attend the ceremonies, which will take place in the memorial park outside headquarters beginning at 10:30 a.m.
A pipe band is scheduled to play.
The police department has been in existence since Jan. 1, 1960. The first officer to die in the line of duty was John J. Nolan, an original member of the force, who had a fatal heart attack while investigating a burglary in Central Islip barely four months later -- on April 17, 1960. He was 27.
The most-recent fallen officer was Glen Ciano, who was killed on Feb. 22, 2009, when he was struck by a drunken driver while assisting another officer in Commack.
He was 45 and is survived by a wife, son and daughter.
Eleven of the officers killed died as a result of motor vehicle-related accidents and incidents, including one who was dragged by the car of a fleeing suspect. Four died after being shot, three died of heart attacks, one of a stroke and one from a fall from a roof during a burglary investigation.
One officer died of carbon-monoxide poisoning working at the police garage.
And Det. Dennis Wustenhoff, an undercover officer involved in a long-term drug investigation, died on Feb. 15, 1990 -- from a car bomb.
This year's memorial will pay special tribute to the first "combat" death in the history of the department, the shooting death of Officer George A. Frees on April 6, 1971.
Frees, who was 28 and had joined the department on Sept. 30, 1968, and his partner were responding to a domestic call on Mount Avenue in Wyandanch, where a child had reported her father had shot her mother, police said.
As Frees stepped from his patrol car, police said he was struck in the neck by rifle fire from inside the home. His partner, Robert Staab, was also shot, hit in the abdomen.
Frees was survived by a wife and three children.