The Bureau of Prisons is testing the idea by allowing MP3 players at a women's prison in West Virginia. If the idea works out, the music players would be allowed for some 200,000 inmates nationwide this year.
The prisoners could choose among a list of about a million approved songs. Obscene or racially charged songs would not be permitted.
The MP3 players would be sold at prison commissaries. A bureau spokeswoman says the music could help prisoners deal with idleness, boredom and stress.
Critics say inmates should not be allowed any more comforts in prison.