Akodon caenosus is a rodent in the genus Akodon found in northwestern Argentina and south-central Bolivia. Since its description in 1918, it has been alternatively classified as a separate species or a subspecies of Akodon lutescens (formerly Akodon puer). The species Akodon aliquantulus, described from some very small Argentine specimens in 1999, is now recognized as a synonym of A. caenosus.

Akodon caenosus is very small, averaging 19.3 g (0.68 oz) in weight, and variable in coloration, but generally brown. The underparts are sharply different in color from the upperparts. The skull has a short rostrum (front part), broad interorbital region (between the eyes), and narrow braincase. The karyotype includes 34 chromosomes. A. caenosus mostly occurs in Yungas vegetation and breeds mainly during the winter. It shares its range with many other sigmodontine rodents, including three other species of Akodon.

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