Holleeder, 61, known in Dutch media by his nickname "The Nose" is best known for his earlier conviction in the 1983 kidnapping of beer tycoon Freddy Heineken.
His lawyers had argued Holleeder was innocent of a number of charges related to the gangland killings, including incitement of the murders and membership of a criminal organisation.
The lawyers said Holleeder was the victim of his criminal reputation.