It is important to understand the unmet needs of family caregivers of advanced cancer patients for developing and refining services to address the identified gaps in cancer care. To explore their needs in Chinese mainland and the possible factors associated with their needs, a self-developed questionnaire was used to survey a sample of 649 participants in 15 hospitals of Shanghai. The data were analysed using descriptive statistics, factor analysis, t-test, one-way ANOVA, and Fishers least significant difference t-test. All statistical analyses were performed using SPSS 13.0. Seven dimensions of needs (maintaining health, support from healthcare professionals, knowledge about the disease and treatment, support on funeral, information on hospice care, psychological support for patients and symptoms control for patients) were extracted from the results by factor analysis. The dimension with the highest score was ‘knowledge about the disease and treatment’ (4.37), and that with the lowest score named ‘support on funeral’ (2.85). The results showed that the factors including burden of payment for treatment, former caregiving experience of family caregivers and length of caregiving time were associated with their needs. Cancer services need to consider how to tailor resources and interventions to meet these needs of family caregivers of advanced cancer patients.