Only four shops refused to sell the games to the underage volunteer
An undercover operation in Dundee has found three-quarters of shops targeted were prepared to sell 18-rated video games to an underage shopper.
A 14-year-old volunteer, recruited by trading standards, was able to buy a game illegally in 12 out of 16 stores.
Only Gamestation, Game, PC World and WH Smith refused to sell the product.
The punishment for breaking the law is up to six months in jail and a fine of up to £5,000. Those caught were warned they could face further investigation.
In some of the stores, pre-programmed warning prompts had been given on tills but the game was sold anyway.
A Trading Standards spokesman said: "It is very disappointing that so many large retailers have ignored their own systems in regard to restricted video game sales.
"Clearly there are issues that need to be addressed, and we will be following up matters with the retailers involved."
Councillor Jimmy Black added: "Do we really want shops selling children games based on gross acts of violence?
"Well done to the four retailers who got it right, but the others are breaking the law.
"They place themselves at serious risk of further investigations by our officers."