The Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) is an observational study of more than 1100 participants across the dementia spectrum. This research note describes the development and features of the neuropsychological research battery, which is available in English and French. The training of staff and procedures for quality assurance are described. The battery assesses learning and memory, processing speed, attention, executive function, visuoperceptual processing, and language, and the available test scores are described. We outline our goals for future work including: (1) increasing the sociodemographic diversity of the participant cohorts, (2) determining the psychometric properties of the battery, (3) establishing robust normative data from control participants followed longitudinally, and (4) examining longitudinal data on individuals at risk of dementia and across the dementia spectrum. The COMPASS-ND neuropsychology data will provide a unique open-access database of deeply phenotyped participants with or at risk of dementia for Canadian and international researchers.