Abstract: A support and guide device for an adjustable seat of the kind fitted to motor vehicles comprises a pair of fixed elongate generally U-shape guides with outwardly turned lateral flanges for attachment to the vehicle floor, a pair of cooperating movable guides for attachment to the seat, the movable guides being elongate and generally U-shape in cross section, the arms of which are shaped to fit over the lateral flanges of the fixed guides, and a latching device housed entirely between one of the fixed guides and the associated movable guide and comprising a shaft carrying one or more teeth for engagement in a row of windows in a ridge formed in the base of the fixed guide to hold the seat in a selected position and so positioned that neither the windows in the guide nor the teeth of the shaft are exposed in any adjustment of the seat.