Pressure ulcers (bedsores) often develop following prolonged sitting especially where people are immobile or are unable to feel discomfort due to injury or disease. This guideline provides health professionals with specific recommendations intended to minimise any risk of developing pressure ulcers when their clients are seated. The guideline covers sitting when people are acutely ill in hospital and, more commonly, where people have a long-term need for prolonged sitting for example after spinal injury. Particular focus is placed upon the need to make sure the physical size and shape of the seat is appropriate for the seated individual. Guidance is provided upon areas where seated individuals require information to help them minimise pressure ulcer development. The advantages and disadvantages of different cushion materials are described.