Primus's musical style is difficult to define. Primus has been called everything from "thrash-funk meets Don Knotts, Jr." to "the Freak Brothers set to music", and has been variously termed alternative rock, alternative metal, funk metal, and progressive metal.
Regarding the band's genre, Claypool has stated "We've been lumped in with the funk metal thing just about everywhere. I guess people just have to categorise you". MTV suggests that Primus is "a post-punk Rush spiked with the sensibility and humor of Frank Zappa". Les Claypool himself once described their music as "psychedelic polka."