Abstract: A toilet seat assembly is provided having a seat that is pivotably supported at its forward end for swinging movement between substantially horizontal and upwardly inclined positions. A power lift mechanism is incorporated in the assembly and is selectively operable by the user to pivot the seat and support the seat in a desired position for assisting the user in moving between seated and standing positions. The power lift mechanism includes an expandible bladder of the bellows disposed at the rear of the seat assembly between a base structure adapted to be secured on the top of a toilet bowl and the pivoted seat that is also mounted on the base structure.