Untitled consists of a hollow brass bar and five steel boxes painted Judd's signature cadmium red color. Moving from right to left, the solid forms double in size, until the final one is sixteen times the size of the original unit. The spaces in between the red boxes undergo a similar doubling in size, from left to right.

Untitled belongs to a group of horizontal progressions that Judd initiated in 1964. Judd was a leading figure of the movement called Minimalism, which denied strict emotional or referential contents, and is associated with serial geometric forms. Judd eschewed any evidence of the artist's gesture; Untitled was made by the industrial fabricators, Bernstein Brothers.