'Very concerned'
Other organisations suing YouTube include the Football Association Premier League, Paramount Pictures and Comedy Central.
Chief executive of the National Musical Publishers' Association (NMPA), David Israelite, said the body was "very concerned about YouTube's approach to copyright".
He added that the body was joining the case "to protect the interests of music publishers and songwriters, whose creative works are being used without permission or compensation by YouTube".
The combined case will be heard in New York.