Aims and Objectives: To inquire into the reasons for family involvement in adult patients' surgical decision-making processes from the point of view of the patients' family., Background: Making a patient the centre of medical decision-making is essential for respecting individual's autonomy. However, in a Chinese society, family members are often deeply involved in a patient's medical decision-making. Although family involvement has long been viewed as an aspect of the Chinese culture, empirical evidence of the reasons for family involvement in medical decision-making has been lacking., Design: A qualitative study., Method: In order to record and examine reasons for family involvement in adult patients' surgical decision-making, 12 different family members of 12 elective surgery patients were interviewed for collecting and analysing data., Results: Three major reasons for family involvement emerged from the data analyses: (1) to share responsibility; (2) to ensure the correctness of medical information; and (3) to safeguard the patient's well-being. These findings also reveal that culture is not the only reason for family involvement., Conclusions: Making decision to undergo a surgery is a tough and stressful process for a patient. Family may provide the patient with timely psychological support to assist the patient to communicate with his or her physician(s) and other medical personnel to ensure their rights. It is also found that due to the imbalanced doctor-patient power relationship, a patient may be unable, unwilling to, or even dare not, tell the whole truth about his or her illness or feelings to the medical personnel. Thus, a patient would expect his or her family to undertake such a mission during the informed consent and decision-making processes., Relevance to Clinical Practice: The results of this study may provide medical professionals with relevant insights into family involvement in adult patients' surgical decision-making., (© 2016 John Wiley & Sons Ltd.)