This study is concerned with issues and influences affecting nurses’ provision of quality care to people with intellectual disability in residential centres. The methodology is a descriptive study conducted through a two-phase mixed methods approach using a dominant-less-dominant design. Phase one, the less dominant phase consisted of a small-scale experience survey of non-nurse experts and two focus group interviews with nurses in clinical practice. Phase two, the dominant phase, consisted of a quantitative survey of a random sample of nurses. Sequential triangulation was employed for data collection where the outcomes of the first phase were used for planning the second phase and for exploring and generating the constructs and variables for the survey. The theoretical perspective for the study is based on the paradigm of care within which nurses operate. In particular, whether or not nurses use the medical and humanistic models to underpin their care of clients in residential centres. The study investigated the dimensions of client care that nurses considered were important to nurses and to clients based on the perception of nurses. Also investigated were the approaches nurses used to evaluate care, the organisational processes used for care and, the influences that organisational management practices has on the nurses’ ability to provide quality care. Results reveal nursing care is only provided at the most basic needs level with physical/health care, safety and emotional care seen as the most important dimensions. Evaluation of nursing care is carried out but is concentrated at the level of physical and personal care. These findings are important and indicate that: 1. Nurses do not consider other dimensions of care to be of significant importance for clients in residential centres and are not providing holistic care. 2. Nurses are predominantly utilising the medical model to underpin the care they provide to clients in residential centres. This study makes an original contribution to knowledge in the following ways: It is the only empirical study in the Republic of Ireland that has looked at quality care as perceived by nurses for persons with intellectual disability in residential centres. It provides knowledge and insight into issues and influences affecting quality of nursing care for persons with intellectual disability in residential centres. It shows that the predominant model that nurses use in centres is the medical model. It advances both a typology and conceptual model useful for understanding, planning and evaluating dimensions of nursing care as needs and the relationship of these needs with dimensions of quality of life as the outcomes of meeting these needs. While the model is descriptive it has a fivefold application: 1. It signposts and provides insights about care that is useful for policy making. 2. It shows relationships between dimensions useful for informing care practices, 3. It draws attention to important issues for professional education and training. 4. It provides management with a guide for planning services responsive to needs 5. It is useful for planning and deciding on areas for investigation and research. Findings add to what is known about the service encounter in residential centres and make a contribution to evidence for practice for persons with intellectual disabilities.