The aim of the present study was to develop a theoretical understanding of elderly patients' experiences of pain and distress in intensive care, using a grounded theory approach. 18 patients, 7 women and 11 men, were interviewed and observed in an intensive care unit (ICU). Their average age was 76.5, varying from 70–85. A model was generated from data, according to which elderly patients' experiences of pain and distress in intensive care can be described as four interrelated aspects: a sensory, an intellectual, an emotional, and an existential dimension. 16 categories form the four dimensions. The categories, in turn, are grounded in a number of interview and observational data. The sensory dimension is formed by the categories physical pain, physical discomfort, fatigue, and breathing problems, and the intellectual dimension by the categories not knowing, difficulty in expressing oneself/not being understood and confused perception of reality. The categories in the emotional dimension are worry, fear, resignation, bitterness, anger/irritation and dependency. Finally, the existential dimension is formed by the categories despair, threat to life and death acceptance. The categories within the four dimensions may be separate, but often they interact and influence each other in various ways. The model is discussed in relation to existing models and definitions of pain, where the intellectual and existential dimensions in particular have not been emphasized in a similar way.