The Beatles' record label, Apple, is suing Apple Computers over its iTunes online music store.
The label has accused the American computer giant of breaching an agreement by using the apple logo and Apple name to promote music products.
Apple Corps, the London-based company owned by Sir Paul McCartney, Ringo Starr, and the widows of John Lennon and George Harrison, has started legal proceedings in the High Court.
It is seeking damages and an injunction to enforce the terms of an agreement made in 1991.
In a statement, Apple Corps said: "The Agreement was concerned with the future use of the name Apple and use of the companies' respective well-known logos of apples.
"Specifically, complaint is made over the use by Apple Computer of the word 'apple' and apple logos, in conjunction with its new application for downloading pre-recorded music from the internet."
The recently launched iTunes enables computer users to download music from the internet.
It has about 200,000 songs available after striking deals with various record labels.
iTunes was welcomed by record companies because users pay to download a music, in contrast to systems like Kazaa in which users share and download music for free.
The company has sold 10 million downloads since it launched in April.
iTunes is available only to Apple Computer users in the United States.