Patient advocacy has been a topic of much discussion in the nursing literature for a number of decades. Ambiguities remain, however, concerning definitions of advocacy in nursing. This qualitative grounded theory-type study aimed to inquire into the meaning of patient advocacy from Iranian nurses' perspective. A purposive sample of 24 nurses (staff nurses, head nurses and supervisors) working in a large university hospital in Tehran was used. Data were collected using in-depth semistructured interviews and reflective diaries kept by the participants. The data were analyzed using elements of Strauss and Corbin's' approach. Advocacy was defined by the participants as: informing and educating; valuing and respecting; supporting; protecting; and promoting continuity of care for patients. The participants also believed that advocacy could take place only if there was respect for patients' individuality and their inherent human dignity. Many of the descriptions given by the participants are consistent with previous research in this area and represent a comprehensive account of their perceptions of patient advocacy.