Background: Pressure mapping systems offer a new technology to assist with pressure care assessment. Data output from such systems can be presented in three forms: numerical data, a three-dimensional grid and a colour-coded pressure map. Objectives: To ( 1) investigate whether sole use of the pressure map was a reliable method of interpreting interface pressures when compared with use of the numerical data; ( 2) establish the inter-and intra-rater reliability of using pressure maps to assess pressure and determine whether reliability depended upon system operator experience; and ( 3) examine whether reliability extended to the range of seating surfaces being tested. Design: A reliability study assessing the ranking of pressure maps recorded by the Force Sensing Array pressure mapping system. Setting: A university occupational therapy department and a community NHS trust. Subjects: Fifteen occupational therapists with experience in pressure mapping and 50 occupational therapy students with no practical experience of pressure mapping. Interventions: Two sets of pressure maps were pre-recorded with an able-bodied adult seated on a variety of surfaces, with maps on each individual surface recorded over a 20-minute period at 2-minute intervals. Subjects ranked both sets of maps in terms of `best to poorest' distribution of pressure. Main outcome measures: Rank orders of ( 1) pressure maps; ( 2) average interface pressures (mmHg); ( 3) maximum interface pressures ( mmHg). Results: The use of pressure maps to interpret interface pressures was a reliable method. Significant agreement existed within ( p < 0.001) and between groups of operators and reliability extended over the range of seating surfaces tested. Conclusions: The practice of using pressure maps to interpret interface pressures in seating as opposed to using the associated numerical data can be supported. This was shown to be a reliable method of assessment by both experienced and less experienced operators across a range of seating surfaces.