Melocactus lemairei is a species of cactus endemic to the Caribbean island of Hispaniola (split between the Dominican Republic and Haiti).

[4] Melocactus lemairei was described by M. Chevalier de Monville, Charles Antoine Lemaire, and Friedrich Anton Wilhelm Miquel, and published in L'Horticulteur Universel.

The cephalium is brown, with white wool and thornlike bristles, and grows up to 10 cm (4 inches).

[6] Melocactus lemairei is listed as Near Threatened on the IUCN Red List, due to it being found in less than 10 locations on Hispaniola, as well as being threatened by collection from the wild, and land clearing for agriculture, industry, and urban development.

This species is threatened by collection from the wild in the Dominican Republic; the cactus is often used as medicine and sold.