AIM: A group-based multisensory activity program (Sensory Day) for residents with dementia was developed, to address the challenge of providing personalised activities within tight operational constraints in residential aged care facilities. METHOD: Fourteen participants with severe and very severe dementia were observed before, during and after participation in one of four Sensory Day sessions. The Menorah Park Rating Scale was used to yield four levels of engagement. The Philadelphia Geriatric Affect Rating Scale was used to identify four affect states. Dementia severity was ascertained by PAS-CIS scores mapped onto the Global Deterioration Scale. RESULTS: Increased levels of constructive engagement and positive affect were observed during participation in the Sensory Day sessions, relative to measures taken before the session. CONCLUSIONS: This novel approach to activity programming demonstrates that it is possible to provide group-based activities for residents with severe and very severe dementia which result in increased engagement and positive mood.