BAR staff were caught by police selling booze to a 14-year-old.
Workers at The Wakefield Tavern, The Rainbow, The Bull and Fairhouse, and the Strafford Arms were fined after an undercover operation.
Officers visited nine pubs in the city centre on Monday in a bid to stamp out sales of alcohol to underage drinkers.
Insp Richard Close, of the Wakefield Central NPT, said: “We are disappointed that four of the premises we visited in this test purchase sold alcohol to our 14-year-old test purchaser and have spoken with the staff involved and issued fines.
“I want to make it clear that we will not tolerate the sale of alcohol to under age young people in Wakefield and are stepping up activity to detect those who are not making proper checks.
“It is well know that alcohol fuels the anti-social behaviour which we are working to tackle in communities and we must all do our bit to restrict its sale to juveniles.
Insp Close warned more test purchase operations would be carried out.
He said: “I would like to add however, that we do have a positive relationship with our licensed premises in Wakefield generally and will be working with licencees as Christmas approaches to ensure we are doing all we can to ensure a safer end to the year.”
Anyone with information should call police on 101.