Musicians including Carlos Santana and Herbie Hancock have criticised Grammy Award organisers for dropping categories from the annual show.
It was announced last month that at least 30 categories would be cut.
The musicians, who argue the changes were made without consulting Academy members, have delivered a letter of protest to the Recording Academy.
But president of the musical organisation, Neil Portnow said a members committee had been consulted.
Contemporary blues, Native American, Hawaiian, and Latin jazz are among the 31 categories that are being cut from the prestitgious awards show.
The musicians are calling for the categories to be reinstated, saying the reductions unfairly target ethnic music.