Mammillaria carnea is a species of cactus in the subfamily Cactoideae.
Mammillaria carnea grows solitary and in clusters up to 20 centimeters tall and 8 to 12 centimeters in diameter, transitioning from spherical to cylindrical in shape. The plant has firm, angular warts that contain milky sap. It features four stiff, pink-brown central spines with black tips, measuring 0.8 to 2 centimeters long. Radial spines are either absent or appear as bristles.
The plant produces funnel-shaped, light pink flowers that are 1.5 to 2 centimeters long and 1.2 to 1.5 centimeters in diameter. Its red fruits contain brown seeds.
Mammillaria carnea is native to the Mexican states of Guerrero, Puebla, and Oaxaca growing on plains and slopes of the deciduous forest at elevations of 500 to 2000 meters.
First described in 1837 by Ludwig Georg Karl Pfeiffer, the specific epithet "carnea" means 'flesh-colored.'