The aim of the present study was to develop a theoretical understanding of quality of care from a patient perspective, using a grounded theory approach. Thirty-five interviews were conducted with a sample of 20 adult hospitalized patients (mean age: 60 years) in a clinic for infectious diseases. Data were analysed according to the constant comparative method. A model was formulated according to which quality of care can be understood in the light of two conditions, the resource structure of the care organization and the patient's preferences. The resource structure of the care organization consists of person-related and physical- and administrative environmental qualities. The patient's preferences have a rational and a human aspect. Within this framework, patients' perceptions of quality of care may be considered from four dimensions: the medical-technical competence of the caregivers; the physical-technical conditions of the care organization; the degree of identity-orientation in the attitudes and actions of the caregivers and the socio-cultural atmosphere of the care organization. The model is discussed in relation to existing theories in the field.