OBJECTIVE: To discuss the clinical manifestations, diagnosis and treatment of undifferentiated embryonal sarcoma (UES) of the liver(UESL) in children. METHODS: A retrospective analysis of the clinical presentation, imaging findings, laboratory data, operation, chemotherapy and survival features in 14 cases of UES of the liver from Jan 1995 to Oct 2008 was performed. RESULTS: Fourteen patients(7 boys and 7 girls) with UESL age ranging from 2 to 11 years (median 6.6 years) were identified. The main symptoms were large abdominal mass(13 patients) accompanied by abdominal pain in 5 cases. One patient developed intermittent abdominal pain. Ultrasonography (US) revealed predominant solid lesion in 10 cases. CT demonstrated predominant cystic masses in 12 cases. Among the eleven patients who underwent complete tumor resection, there were six patients still alive. Two patients underwent partial tumor resection and one underwent biopsy all died. Eight patients received multiagent chemotherapy, there were six patients still alive, the survival rate was 75% (6/8). Three patients received chemotherapy with 3 kind of drugs and three patients refused chemotherapy all died. About 60% (6/10) patients with UES of the liver in staging I and II survived. Patients with UES of the liver in staging III and IV all died after operation. Follow-up of 9 months to 9 years and 8 months showed 6 patients using multiagent chemotherapy alive. Eight patients suffered tumor recurrence from 2 to 30 months after operation and all of them died. Another patient died of heart failure related to chemotherapy. CONCLUSION: Discrepancy of imaging between US and CT is one of the important characteristics in UES of liver. Complete tumor resection and multiagent adjuvant chemotherapy can improve the survival rate significantly.