Two marketers acting on behalf of claims management companies have been fined £250,000 by the Information Commissioner's Office, in the first case of its kind.
The two men sent millions of unsolicited texts to consumers about claiming for mis-sold PPI.
They breached regulations that stop mobile phones and landlines being used unless they are requested by the owner.
ICO director of operations Simon Entwisle said the public had become increasingly concerned about the illegal marketing texts and calls.
"These are often made by rogue companies claiming to offer pay outs for accidents a person has never had or PPI claims that they are not necessarily entitled to," he said.
"While companies can phone people to sell them the latest product or service, the law states that individuals should not receive unsolicited texts or automated marketing calls unless they have given their permission.
"We know many companies are failing to do this and two individuals responsible for sending millions of illegal marketing messages are now facing six figure penalties unless they can prove otherwise.
"It would be inappropriate to provide further comment until both individuals have had the opportunity to reply, but we are already working to identify other individuals and companies involved in these unlawful practices."
The ICO had received almost 30,000 complaints about PPI cold-calling, according to latest figures. Entwisle said it would be taking further action against marketers using similar tactics.
