This chapter describes how design has been applied to the development of a system for supporting the prescription of wheelchairs. With an ageing population there is likely to be a continued rise in wheelchair usage, as well as wheelchair modifications for specific needs such as specialist seating and the addition of assistive devices. Ensuring the ease of use, stability, safety and performance of wheelchairs both occupied by, and attended to by older adults is an important consideration. This chapter describes the design methods employed in the development of WheelSense ®, a system for use by wheelchair prescribers to support the assessment, adaptation and tuning of wheelchairs to meet individual needs. The system development has required a multidisciplinary approach bringing together designers, engineers, human factors specialists, clinical specialists alongside end-users and stakeholders. The resulting WheelSense ® system combines electronics and a weighing system in a folding platform. It is supported by a handheld device and graphic user interface (GUI) for guiding the prescription process, enabling data entry and to support education of the wheelchair user chair.