Recently, an international consensus diagnostic criterion for cancer cachexia was proposed. The aim of the study is to assess the prevalence of cachexia in patients with advanced cancer and to assess the current status of the diagnosis and management of cancer cachexia. A total of 390 patients with advanced cancer were included. There were 140 patients with cachexia and the prevalence was 35.9%. The prevalence was highest in pancreatic cancer (88.9%), followed by gastric cancer (76.5%) and esophageal cancer (52.9%). Sixty-three patients with cancer cachexia have CT scans available for muscle mass evaluation and 98.4% were sarcopenic. Cachectic patients have a significantly lower overall quality of life and a higher symptom burden. According to oncology physicians, only 33 patients were considered to have cancer cachexia. The false negative rate amounted to 76.4%. The positive rate was related to the body mass index and Eastern Cooperative Oncology Group performance status of the patients. There were few types of pharmacological approaches for cancer cachexia and more than half of cachectic patients did not receive any anticachexia treatment. These results indicate that the prevalence of cachexia in advanced cancer patients was high. However, cancer cachexia was rarely recognized and clinical management for cancer cachexia was very inadequate.