Drink sales dropped more than ten per cent since the public smoking ban came into effect in Scotland, pub bosses said yesterday.
Food sales also dropped three per cent, according to the Scottish Licensed Trade Association.
"This ban will put hardworking licensees out of business and many bar staff," said SLTA chief executive Paul Waterson.
The findings, described as "a massive stay-away by Scotland's pub regulars", came from a survey published yesterday in Edinburgh.
It said 46 per cent of licensees reported a drop in visits by regulars since the ban on March 26, and only five per cent reported an increase.
The impact on sales was similar, with 51 per cent reporting regulars were spending less and only seven per cent more.
Mr Waterson, owner of the Flagship Hotel group, said: "We were told business would improve as a result, something we never believed.
"Now even our prediction of seven per cent loss of business has proved optimistic.
"Drink sales look to have dropped over ten per cent and surprisingly food sales are down three per cent."
The SLTA survey said losses had not been counterbalanced by new business from non-smokers, with 20 per cent reporting more new customers or more frequent visits but 17 per cent reporting fewer.
Mr Waterson said land-locked pubs with no outdoor areas suffered most as customers either stayed at home or went elsewhere.