Pilosocereus robinii is a species of cactus known by the common name Key tree-cactus. It is native to the Florida Keys in the United States. It also occurs in Western Cuba and the Northern Bahamas. It has been erroneously reported from Puerto Rico, the Virgin Islands, and Mexico. It is a rare species which is threatened by the loss of its habitat. It is a federally listed endangered species of the United States.