Authorities have issued directives to the voters for full compliance with health protocols due to the ongoing Covid-19 pandemic.
The elections are being held in 3,100 polling stations in the provinces of East Azerbaijan, Isfahan, Ilam, Alborz, Zanjan, Khuzestan, Kurdistan, Kermanshah and Golestan for the 11 remaining seats in the 290-member Parliament.
All polling stations were disinfected on the eve of the election.
It is also obligatory for the voters to wear face masks and gloves and observe social distancing at the polling stations.
Meanwhile, the runoff parliamentary elections in Tehran and two other cities will be held next year along with the nationwide presidential and city council polls.
The first round of the parliamentary elections was held on February 21, and the runoff was initially slated for April 17 but was delayed because of the coronavirus pandemic.