Mammillaria carmenae, the Isla Carmen pincushion cactus, is a species of flowering plant in the family Cactaceae.

The clustered egg-shaped stems, 3–4 cm thick, are covered in creamy-coloured yellow down and bristles.

In spring they bear pale cream or pink-tinged flowers with yellow centres.

[1] Mammillaria carmenae was named by Marcelino Castañeda y Nuñez de Caceres in 1953, after his second wife, Carmen Gonzales-Castaneda.

It has gained the Royal Horticultural Society's Award of Garden Merit.