Abstract: A portable seat cushion having upper and lower seat pads. The upper seat pad is hingedly connected to the lower seat pad forming a hingeline therebetween. The lower seat pad includes first and second cushion members. The first cushion member includes top, bottom and side surfaces. The second cushion member is secured to the bottom surface of the first cushion member. A cavity is formed in the second cushion member such that when an individual sits on the lower seat pad a portion of the first cushion member is free to recess or sag into the first cavity. The upper seat pad includes a lower back support positioned adjacent the hingeline formed between the upper and lower seat pads. The seat cushion is formed from high density polyurethane.