This qualitative study identifies areas of expertise and deficits in the specific knowledge and practical skills of nurses in the care of dying patients with profound learning disabilities in one NHS Primary Care Trust in the UK. In response to these findings, we have developed a simple observational checklist applicable to profound learning disability nursing to identify disease-related personality and physiological changes. The method consists of a descriptive case study of five nurses qualified in learning disabilities nursing, using semi-structured interviews. The disease trajectory was used as a framework of reference to guide the data analysis. Themes showed were ‘certainty of knowing’ about disease-related changes in patients' habits and behaviour and ‘uncertainty and ambiguity’ in the patho-physiology of advanced diseases and disease progression. This study interprets a lack of patho-physiological knowledge in both malignant and non-malignant diseases leading to delayed diagnosis and timely intervention. Timeliness of observation and intervention are emphasised.