Researchers have rejuvenated a 53-year-old women's skin cells so they are the equivalent of a 23-year-old's.
The scientists in Cambridge believe that they can do the same thing with other tissues in the body.
The eventual aim is to develop treatments for age-related diseases such as diabetes, heart disease and neurological disorders.
The technology is built on the techniques used to create Dolly the cloned sheep more than 25 years ago.
The head of the team, Prof Wolf Reik, of the Babraham Institute in Cambridge, told BBC News that he hoped that the technique could eventually be used to keep people healthier for longer as they grow older.