To date the only treatments available have been those which mask symptoms, such as CDs of ocean waves, or psychological techniques to help people cope better.
Scientists have now found that playing sufferers the same tone which they "hear" in their mind stops auditory brain cells from creating the perceived noise.
With ACR, the brain manages to "unlearn" the neurological processes which cause it to generate the "phantom" sounds sufferers associate with tinnitus.
Researchers say a new trial comparing ACR against a sham treatment in 63 people with long-term tinnitus, provides hard evidence it works.
Volunteers were first asked to match their tinnitus tone to one of a range played to them.
This tone was then played to them through in-ear headphones four to six hours a day, for 12 weeks. They were then taken off it for four weeks, before being put on it again for regular intervals for another 22 weeks.
At the end of the 40 week RESET trial, led by Professor Peter Tass at Jülich Research Centre in Germany, about seven in 10 who received active treatment said their tinnitus had got quieter and less annoying. On average, it halved the intensity of their symptoms.
Those given the sham treatment experienced "limited and non-significant changes".
The results are being presented tomorrow (Tuesday) at a conference held at the British Medical Association in London. The study has been published in the journal Restorative Neurology and Neuroscience.
The Tinnitus Clinic, based in Harley Street, is introducing the treatment, although it comes with a £4,500 price tag.
Josephine Swinhoe, managing director, said it was also funding a larger UK trial run by Nottingham University. It hoped to approach the National Institute of Health and Clinical Excellence (Nice) in the future "with the hope of making it more widely available".
The British Tinnitus Association said the results were "encouraging" but said a larger, independent trial was needed.