Abstract: An adjustable arm rest assembly comprises an arm rest; a horizontal plane attitude adjustment, adapted to support the arm rest; a vertical elevation adjustment; and, an arm rest bracket. The vertical elevation adjustment is adapted to be pivotally connected to the horizontal plane attitude adjustment to cooperably facilitate hinged adjustment of the horizontal attitude of the arm rest. The horizontal plane attitude adjustment and the vertical elevation adjustment have co-operable detent and block members adapted to be mutually resiliently secured in ones of a plurality of operably aligned registers corresponding to ones of a selectable plurality of horizontal attitudes for the arm rest.