Cyrtostylis reniformis is a terrestrial, perennial, deciduous, herb with a single kidney-shaped, heart-shaped or almost round leaf 15–40 mm (0.6–2 in) long and 10–30 mm (0.4–1 in) wide.

Up to eight dark reddish brown, or rarely yellowish flowers 11–14 mm (0.4–0.6 in) long are borne on a flowering stem 50–150 mm (2–6 in) high.

The petals are similar in size and shape to the lateral sepals and curve downwards.

[2][3] Cyrtostylis reniformis was first formally described in 1810 by Robert Brown and the description was published in Prodromus Florae Novae Hollandiae et Insulae Van Diemen.

[6] Common gnat-orchid is widespread and locally common in all Australian states and the Australian Capital Territory, except Western Australia.