One role of occupational therapy in the rehabilitation of people with traumatic brain injury is to determine the impact of cognitive and perceptual deficits on client performance of occupational tasks. Existing methods that can be used to assess cognitive deficits include standardised instruments and observations of everyday task performance. Few of these assessment methods are able to adequately link problems of cognition with problems with self-maintenance, productivity and leisure tasks relative to a client's expected occupational roles. The Perceive, Recall, Plan and Perform (PRPP) System of Task Analysis enables observation of performance of any functional task and allows therapists to identify the cognitive basis of disordered performance. The results of this assessment are then used to establish and evaluate client-centred goals and guide subsequent intervention. This article describes the PRPP System of Task Analysis and outlines how it can be used by occupational therapists involved in the management of adults with traumatic brain injury. Specifically, an in-depth case study illustrates how this innovative model of assessment has effectively been used to promote client learning of self-maintenance skills.