This cross-sectional study among nurses at the hospitals of the Tehran University of Medical Sciences aimed to investigate the extent of involvement in patient advocacy practice among nurses. Participants (n=330) were selected using proportionate systematic random sampling. Data were gathered through patient advocacy questionnaires and analysed using descriptive/inferential statistics. The average of nurses' patient advocacy practice was 3.848+ 0.304 (possible range 1-5). One third of the participant nurses had high scores in practising patient advocacy, two thirds of them had scores in the medium range and 0.6% of nurses had low scores. The majority of nurses (83.5%) declared their commitment to patient advocacy as high, and 42.5% believed they had enough ability to practise advocacy.