Sixty people have been arrested by gardaí targeting the sale of drugs in Dublin, Cork and Wexford.
Two hundred charges, mostly involving the sale and supply of heroin, have been brought against those arrested.
Fifty homes were searched during the operation, which lasted six months, and a sizeable quantity of heroin was seized.
The head of the Drugs and Organised Crime Bureau, Detective Chief Superintendent Michael O’Sullivan said the operation would lead to serious shortages of heroin on the streets.
He said: "It will have a very significant effect. Certainly in Cork and Wexford, there will be great difficulty in buying heroin over the next number of weeks.
"In inner city Dublin, there will be a serious shortage in the supply of heroin, and also in the manpower to distribute it. This will have a serious disrupting effect."