Three men convicted of drug trafficking were hanged on Sunday in the town of Arak in central Iran, Fars news agency reported.
The men were identified only as Sh N, convicted of smuggling more than 2.5 tonnes of opium, Behrouz K, arrested with 583 kilos (1,283 pounds) of opium and V Gh, found guilty of possessing about 1.5 kilos (three pounds) of heroin, Fars said.
It did not say whether the executions were carried out in prison or in public.
The latest hangings bring to at least 164 the number of people executed in the Islamic republic so far this year, according to an AFP count based on news reports. In 2008, Iran executed 246 people.
Tehran says the death penalty is a necessary tool for maintaining public security and is only applied after exhaustive judicial proceedings.
Murder, rape, armed robbery, drugs trafficking and adultery are all punishable by death in Iran.