Atmospheric Sludge Metal is performed with an emphasis on atmospheric and textured riffs. Pioneered by bands such as Neurosis, Isis, Cult of Luna, Rosetta, and Pelican, the style is characterized by heavy and distorted riffs slowly building on the crescendos often associated with Post-Rock. This is why this style is sometimes called Post-Metal.

But Atmospheric Sludge Metal has evolved from Post-Metal, adding Sludge Metal riffs and screams/gutturals associated with Crust Punk à la His Hero Is Gone (who were heavily influenced by Sludge Metal) and other forms of Hardcore. Post-metal, however, does not have these characteristics, often empathising atmosphere more than vocals and being outright instrumental (Russian Circles).