Abstract: A floor-mounted anchor unit for toilets comprising---in association with an upstanding sewer pipe riser set before placement of the floor---a horizontal annular toilet attachment flange on the floor adjacent and in register with such riser, a horizontal annular sub-flange surrounding the riser in spaced relation below the toilet attachment flange and engaged beneath a portion of the floor, and a plurality of vertical, circumferentially spaced screws connected in holding relation between said flanges radially outwardly of the riser; characterized by the toilet attachment flange being initially detached, and means including said screws temporarily assembled with the riser and supporting the sub-flange in position on said riser preparatory to placement of the floor thereabout and over the sub-flange, said means being removable at least in part and with the screws to then permit said connection of said screws between the toilet attachment flange and the sub-flange.