Phyllochaetopterus gigas, new species, was found living associated with a whale fall lying at 2892 meters depth in the Monterey Submarine Canyon, off California, U.S.A. The new species was found over a period of nine yr adjacent to, on, or in sediment lying over, the baleen of the whale fall. Phyllochaetopterus gigas is characterized by its large size (up to 30 cm preserved body length), long palps, coloration, and patterning of the ventral shield of the anterior region (region A), the presence of 4–6 large cutting chaetae on each parapodium of the fourth chaetiger (a4), the shape of these chaetae (with a pear-shaped head, some small lateral teeth on the edge), and presence of two middle-region (region B) chaetigers with foliose notopodia. The new species is compared to other Phyllochaetopterus species and appears to be, at least in part, a deposit feeder.