Mammillaria fittkaui is a species of succulent plants. The Mammillaria genus is generally found in the southwest United States and Mexico, with some spread into the Caribbean. The huge genus contains at least 275 species of highly variable forms.
Stems of Mammillaria fittkaui are cylindrical, bright green to dark green to gray-green, to 10 cm (3.9 in) high, 4 – 5 cm (1.6 – 2 in) in diameter. It is easy to grow, and will produce irregular mounds with time. Fairly fast in growth. Flowers are white, to 15 mm (0.6 in) long and 20 mm (0.8 in) in diameter. Fruits are white to pink, with pinkish base, to 7 mm (0.3 in) long.