Objective To investigate the prevalence of insomnia in the elderly with advanced cancer, and to explore the differences in their symptoms, emotions and quality of life between those with and without insomnia for the risk factors of insomnia. Methods From July 2019 to December 2020, MD Anderson symptom inventory (MDASI), hospital anxiety and depression scale (HADS), patient health questionnaire-9 (PHQ-9), insomnia severity index (ISI), and EuroQol five dimensions questionnaire-5L version (EQ-5D-5L) were used to investigate the patients (aged ≥65 years) with advanced cancer from 10 centers over China. Finally, a total of 696 patients who met the inclusion criteria were enrolled in the study. All data analyses were conducted with SAS 9.4 software. Student′s t test or Chi-square test was used for intergroup comparison depending on different data types. Multivariate logistic regression analysis was employed to explore the risk factors of insomnia. Results The prevalence of mild or more severe insomnia was 31.9%(222/696) in the elderly with advanced cancer. The patients with insomnia had higher incidences of symptom burden and psychological distress, and lower score of quality of life (all P<0.001). Depression and anxiety were risk factors of insomnia (OR=0.254,95%CI 0.105-0.119, P=0.002; OR=0.286,95%CI 0.615-0.687, P=0.005). Conclusion Attention should be paid to insomnia among the elderly with advanced cancer. Even mild insomnia can negatively affect symptom burden, psychological distress and quality of life in the patients.