The Health Ministry said Friday that 1,178 people had been diagnosed with the infectious disease in the past 24 hours, bringing the total caseload to 6,204,224.
With 19 more deaths recorded, the total number of those killed reached 131,821, it added.
No deaths were reported in 22 provinces, while four provinces recorded only a single one, according to the ministry.
It is the first time in 22 months that Iran registers a daily death toll below 20 individuals.
The downward trend is seen as a result of a stepped-up vaccination campaign in Iran in recent months.
So far, the ministry said, 121,982,424 doses of vaccines have been administered in the country of around 84 million. Out of that figure, 9,505,625 people have received the third dose.
Despite the decline in numbers, officials have been warning people not to take lightly the health protocols against the COVID-19 infection as Omicron, a new variant of the coronavirus, is spreading rapidly through many world countries.