Abstract: The present invention has as an object a foldable staircase for vehicles, for examples in airplane, which, once folded, is housed in a compartment provided in the fuselage.This staircase comprises:a carriage (4) slidably mounted in the compartment (1) which carriage receives, in an overhanging manner, a foldable staircase structure (5) which, when it is housed in the compartment, is folded and extends toward the opening (3) of this latter,a motor mechanism (6) either for driving the carriage (4) toward the opening (3) and extracting the structure from the compartment (1) outside of which it will be deployed, or for restoring the structure into the compartment after this latter has been folded and conducted at the time of folding into the axis of the compartment,and motor means (7) for unfolding or re-folding, along a vertical plane, the structure (5) when this latter is outside of the compartment (1).