Abstract: A support column for height-adjustable seats is described, in which the tubular support element housing the guide bush of the seat raising element and the relative control mechanism is formed from a plastic coupling element which is provided externally with a Morse taper for fixing the column to the seat support base, and is connected in an axially rigid manner to the guide bush so as to fix it into the support element, and from a strengthening element in the form of an unworked tube mounted surrounding the coupling element.