The men were identified as Abdul-Aziz Ismaeil Zehi, Abdul-Jamal Shahbakhsh and Ali-Akbar Shahbakhsh.
The official state broadcasting corporation IRIB said in a report on its website that the men were hanged earlier in the day in a prison in the provincial capital Zahedan.
It said that they had been convicted of drug smuggling and taking part in armed attacks.
Iranian authorities routinely execute dissidents on bogus charges such as armed robbery and drug trafficking.
