More than a million Iranians out of a population of 77 million drink alcohol, a participant in the country's First World Congress on Alcohol Abuse was quoted Tuesday as saying.
The ISNA news agency attributed the comments to Dr Reza Afshari, president of the Asia Pacific Association of Medical Toxicology, based on a year-long study that ended in March 2013.
"More than a million Iranians drink alcohol. Thirty percent of drinkers are women and 70 percent men," Afshari said.
At the end of last year, Iran opened its first detoxification centre for alcoholics, whose number the Iranian authorities estimate at 200,000 nationwide.
Drinking, possessing and selling alcohol have been illegal since the 1979 revolution, and only the Christian minority has the right to produce it.
Because of the scale of the problem in Iran, police often mount roadside breath-test checks, with offenders being fined two million rials ($60, 44 euros).
Much of the alcohol consumed in Iran is smuggled in from Iraqi Kurdistan, but Iranians can buy locally made alcohol cheaper.
Media reports often speak of people dying after drinking adulterated alcohol.