The British Beer & Pub Association (BBPA) is launching a national poster campaign aimed at encouraging drinkers who look under 21 to carry ID.
The campaign, which will be rolled out through all BBPA members early next month, is designed to be a "gentle reminder" to young people to carry ID.
Pub companies will be sent posters which can be displayed in pubs letting those who appear under 21 know they may be asked for proof of age.
The posters will spell out what acceptable forms of ID are - a card with the PASS logo, a photographic driving licence or a valid passport.
Martin Rawlings, director of pub & leisure at the BBPA, who is helping launch the campaign, said: "There needs to be a culture where people are expected to be asked for ID.
"With this scheme we are trying to build awareness of the problem of underage sales in the trade.
"Hopefully it will have a dramatic effect on reducing sales to those under 18."
The initiative, which is already in place in a number of pubs, follows a similar exercise in supermarkets and off-licences.
Mr Rawlings added: "The Home Office asked supermarkets to come up with an idea to cut down on underage sales.
"We looked at what they came up with and thought it was a good idea."
The launch of the scheme coincides with a call from Andrew Cunningham, licensing chief at the Department for Culture, Media and Sport, for "strong action" from pubs, after evidence that supermarkets had made progress on underage sales.
During last month's National Pubwatch Conference in Chester, Mr Cunningham told delegates: "The issues of ID cards, PASS accreditation and NO ID NO SALE must be pressed home to pubs."
Lou Hogg, licensee at the Old Crown in Hesket Newmarket, Cumbria, said he welcomed the scheme. "I'm all for it. At the end of the day it's a safeguard for the people who look young," he said.