This study aimed to describe the types of support that ward nurses provide to families of patients with advanced cancer in surrogate decision-making and the factors associated with the difficulties these nurses experienced . An anonymous self-administered questionnaire survey was conducted among 285 nurses practicing in the cancer wards of four facilities. In total, 230 (80.7%) nurses provided support in surrogate decision-making, such as attending discussions. Additionally, 41 (17.8%) of the respondents often experienced difficulties performing this task. Results of a binary logistic regression analysis showed that the factors associated with the nurses’ recognition of difficulties were frequency of surrogate decision-making support requirements (OR=2.41, P=0.009) and incomprehension of the relationships between patients and their families (OR=2.41, P=0.009). To promote nurses’ support in surrogate decision-making, we suggest routinely collecting information on the relationships between patients and their families.