The official IRNA news agency said "serial killer" Mehdi Faraji, convicted of murdering five middle-aged women who boarded his minibus, was hanged in public in the city of Qazvin, northwest of the capital Tehran, on Thursday.
Two more men, Hamid Ranjbar and Hamid Reza Baqeri, were also hanged in public after being convicted of armed robbery and abduction. They were executed in the southern city of Shiraz.
Another two, Masoud Dehqan and Mehdi Alipour, were hanged in public in the same city after being found guilty of rape, the IRNA report added.
In addition, two men convicted of drug trafficking were hanged on Thursday in a prison in the northern city of Sari, IRNA reported, quoting the city's prosecutor Asadollah Jafari. The report did not name the convicts.
Also, four men convicted of drug smuggling were sent to the gallows in a prison in the central city of Yasouj, IRNA cited a local prosecution official as saying, but did not name the men.
Another man, meanwhile, was hanged on Monday for drug smuggling in the city prison of Behbahan in the southwestern province of Khuzestan, the provincial justice department said on its website. It gave no other details.
The latest hangings bring to 143 the number of executions reported in Iran so far in 2011, according to an AFP count based on media and official reports.
Iranian media reported 179 hangings last year. But international human rights groups say the actual number was much higher, making the Islamic republic second only to China in the number of people it put to death.
Iran says the death penalty is essential to maintain law and order, and that it is applied only after exhaustive judicial proceedings.