Abstract: A dynamic posture chair is disclosed which is capable of use in a range of sit/stand positions. The chair includes a mobile base that is selectively movable by the user and the chair member that is mounted to the base with a tilt mechanism that enables the chair member to be selectively and infinitely tilted over a predetermined of tilt positions while resistively restraining the chair member in the selected tilt position. The chair member includes seat and back members that relatively subtend an angle in the range of about 120 degrees to 135 degrees. The chair member has a uniquely shaped fixed seat/back contour that instantly supports in comfort the back, buttocks and thighs of the user in its lowest and highest vertical positions, and in all positions in between.