The design and organization of a large-scale experimental study on the effect of emotion-oriented care is described. The research project aims to investigate the effect and the cost-effectiveness of emotion-oriented care on demented elderly residents of nursing homes and their professional carers. Besides an evaluation of the effect and costs of emotion-oriented care, the project intends to describe the implementation process of the intervention itself, including the educational courses for the nurses and on-the-job training. Emotion-oriented care as applied in this study is based mainly on the validation approach of N. Feil, developed in the seventies and eighties, but also utilizes insights from other approaches in psychogeriatrics, such as: reality orientation training, reminiscence and sensory stimulation. The study started in April 1996, and data are being collected during 1997. The processing of data and analysis will take place in 1998, and the results will be available during the spring of 1999.