Research suggests that for many older people with dementia living in residential care, communication with staff often provides the most significant element of their day. It seems likely that the quality of the interactions provided by staff during their care of people with dementia will be an essential factor in affecting the person's quality of life. Research also suggests that the attitudes of nursing and care staff towards people with dementia is a central component in the quality of care they deliver, however, to date, there has been no empirically established evidence that staff attitudes have a direct effect on the quality of life of the people cared for. This study aims to examine the impact of staff attitudes on both the quality of care delivered and on the quality of life of residents and to examine whether there are any changes in any of these areas as a result of training and development interventions. The research includes a review of existing attitude measurements and the development of a new attitude scale for use with dementia care professionals, offering evidence for its reliability and validity. In order to evaluate quality of care, a new observational technique is developed, which draws on previous observational methodologies, with a focus on the behaviour of staff during their care of people with dementia. Results suggest that staff with more 'hopeful' attitudes about people with dementia are more likely to engage in social interactions and activities with residents and use more quality indicators (such as giving choice and information) during physical care tasks. The study also showed improvements in staff attitudes, the quality of care provided and in resident well-being following a number of training and development inputs. The implications of the results are discussed in relation to the limitations of the research.