Prisoner Khalil Mohammadi was executed on 30 October for drug-related offences in Parsiloun prison in Khorramabad, Lorestan Province.
Mohammadi and another prisoner were transferred to solitary confinement for execution on 29 October.
There is no information about the identity or fate of the other prisoner.
Mohammadi, a father of two from Harsin, Kermanshah Province, was arrested and sentenced to death several years ago.
According to statistics compiled by the Kurdistan Human Rights Network (KHRN), at least nine prisoners were executed in Khorramabad, Hamadan, Rasht, Khoy and Karaj prisons during October.