Objective To evaluate the knowledge and performance of surgical residents regarding the person from whom informed consent should be taken for surgery and from whom the consent is taken in practice.

Materials and methods This study was done in 2013. The population of this study was all residents of urology, surgery, orthopaedic surgery and gynaecology of Tehran and Iran University of Medical Sciences. The study tool was a self-administered questionnaire, containing questions on their knowledge and performance regarding informed consent acquisition from patients with different conditions in terms of age, sex, marital status and their capacity to make treatment decisions.

Results A total of 213 residents participated in the study (response rate=51.9%). The mean score of the participants’ knowledge was 72.95 out of 100. There was no significant correlation between the residents’ knowledge and performance. Regarding a competent married male patient, 98.2% of the residents knew that the person’s consent was enough, but only 63.6% obtained informed consent only from the patient. These percentages were 69% and 19.7% for a competent married female patient, respectively. For a competent single male patient, 90.9% of the residents were aware that the patient’s consent was enough, while only 40% of the residents obtained informed consent only from the patient. These percentages were 65.3% and 16% for a competent single female patient, respectively.

Conclusion Despite the residents’ average knowledge of patient autonomy, this right is not observed for female patients, and their treatment is subject to consent acquisition from other family members.