Foldaway ramp (1) for the access of disabled people's wheelchairs and children's pushchairs aboard vehicles (B) with low floors (P), comprising a platform (3), displaceable between a retracted position and an extracted position, with respect to a supporting frame (2), provided underneath the floor (P). Cam means (8, 27) are provided for controlling slant of the platform (3), during the final phase of its displacement towards the extracted position, from a position parallel to said floor (P) to a position which is slanted downwards, where the front edge (11) of the platform (3) rests on the ground (G), and the return of the platform (3) to said position in which it is parallel to the floor (P) during the initial phase of its displacement towards said retracted position, by effect respectively of raising and lowering the rear side (19) of said platform (3) operated by said cam means (8, 27).