As the field of prospective memory (ProM) research has expanded, recognition of the need to make a clinical diagnosis of ProM difficulties has also increased. In addition, there is increasing interest in understanding in more detail the ways in which ProM deficits differ in populations with different underlying neurological dysfunctions. While questionnaires, naturalistic studies and laboratory studies have all been invaluable in furthering our understanding of ProM, until recently there has not been a standardised clinical measure. The Memory for Intentions Screening Test (MIST) was designed to be a relatively brief clinical measure of ProM in clinical populations. The MIST allows for comparisons of performance with event-based and time-based cues. The MIST also has some items with a short (2-minute) and some with a long (15-minute) delay period. Finally, the MIST contains items that require a verbal response as well as items that require an action response. The MIST has now been used in studies of normal ageing as well as a range of clinical populations, including individuals with traumatic brain injury, individuals with HIV infection and individuals with schizophrenia. The psychometric properties of the MIST have been found to be acceptable. Data from each of the clinical populations that have been administered the MIST demonstrate good specificity and sensitivity of the measure as well as the ability to begin to make comparisons about different patterns of performance between disease types.