Cosmos pacificus is a Mexican species of plants in the family Asteraceae.

It is native to southwestern and west-central Mexico from Sinaloa to Chiapas.

[1] Cosmos pacificus is a branching annual up to 200 cm (80 inches) tall.

[1] The oldest name for the taxon is Cosmos caudatus var.

[2] In elevating the taxon from varietal level to species, Melchert opted to forego the common (but not mandatory)[3] custom of using the varietal epithet as specific epithet, choosing instead to create a new name, Cosmos pacificus.