It is the only genus in the monotypic family Orobdellidae.

[1][2][3] They are large annelids, with the largest species (Orobdella octonaria) exceeding 20 cm (7.9 in) in length, but some are much smaller: mature individuals of Orobdella koikei can measure only 4 cm (1.6 in).

They inhabit the banks of mountain streams and feed on earthworms.

[2][3] The majority of species are endemic to Japan; two species are known from Taiwan, one from Korea, and one from Russian Far East.

[4] Orobdella contains 21 species,[4] including the following:[2][3][4]