The species of the genus Oreocereus grow shrubby, branching only sparsely from the base and reach heights of growth of 2 to 3 meters.

The erect, pendulous or rarely extended cylindrical shoots are notched or warty between the ribs.

As they are covered with woolly white fuzz (modified spines), a few species in this genus are sometimes known as the old-man cactus,[3][4] a generic name that also refers to Cephalocereus senilis or Espostoa lanata.

[nb 1] The tubular to funnel-shaped, more or less radially symmetrical, orange to red to violet flowers arise near the shoot tip, or sometimes from the terminal cephalium, and open during the day.

The spherical to oblong fruits contain broadly oval, dull or shiny black seeds.