The Chilean rock rat (Aconaemys fuscus) is a species of rodent in the family Octodontidae.

[2] This species is endemic to parts of Argentina and Chile in the high Andes in South America.

In Argentina, it is restricted to thick forests of bamboo and Nothofagus dombeyi, but in Chile it is found in monkey puzzle (Araucaria) and southern beech (Nothofagus) forests, and above the tree line, usually among tussocky grass.

[1] The Chilean rock rat is a semi-fossorial species and constructs a network of shallow tunnels and runways with entrances every metre or so.

These burrows resemble those of Spalacopus and Ctenomys and are sometimes also used by Akodon longipilis and Geoxus valdivianus.