Campaigners claim thousands of children are exposed to alcohol adverts during popular TV shows.
Alcohol Concern said the number of booze commercials rises "dramatically" between 3pm and 5pm - the time when children come home from school.
Its study raises new fears about future problems with obesity and liver damage among young people.
The group is now calling for a 9pm watershed to be introduced for alcohol ads in a bid to reduce the number of children who see them.
At the moment, drink adverts can be broadcast at any time as long as they are not shown during programmes where children make up more than 20% of viewers.
But Alcohol Concern says it is impossible for parents to predict when drink commercials will be broadcast.
Chief executive Srabani Sen said: "A watershed ban is the only way to give parents the peace of mind of knowing that their children can be kept safe from the influence of advertising."
But a spokesman for the Broadcast Committee of Advertising Practice (BCAP) ruled out a pre-9pm ban, saying: "At this time BCAP is not considering a change to its alcohol codes, including the rules on where and when in the schedules alcohol ads may appear."