The care of patients coping with chronic illness is a major priority and challenge to nursing. This is a result of the increased incidence of chronic illness and a recognition that effective care can significantly retard its progression and interference in the life of the patient. However, because most care in chronic illness is on an ambulatory basis, effective care is directly related to the extent to which patients practice self-care. As a result, the role of the nurse in working with chronically ill patients is less as a provider of treatment and more a facilitator of self-care by the patient. In addition, characteristics of chronic illness and treatment emphasize the complexity of factors and variables that impact on care. The model of self-care in chronic illness has been described to guide nurses in assessing the major issues that influence patients' participation in self-care. Regular assessment of patients' perceptions and circumstances relative to the variables identified by the model will guide nurses in promoting and supporting self-care by chronically ill patients.