Background: Leiomyosarcoma is a common subtype of soft tissue sarcoma originating from smooth muscle. We evaluated the clinical course and treatment outcome of patients with metastatic leiomyosarcoma. Methods: We retrospectively reviewed the records of patients at the University Hospitals Leuven. Results: We identified 122 patients with metastatic leiomyosarcoma, 77 female, median age 59.5 years. Most patients developed leiomyosarcoma in the extremities (35%), the uterus (20%) or the abdomen (19%); 69% developed metachronous metastasis, 31% had synchronous metastatic disease. Most patients (74%) received palliative systemic therapy. The most common first-line treatments were doxorubicin (n = 47) and an anthracycline combined with an alkylator (n = 28). The objective response rate to first-line palliative systemic therapy was 20% and the median progression-free survival was 4.9 months (range 0.1-17.1). The median survival from diagnosis of metastasis was 20.5 months (range 0.4-126.9). On multivariate analysis, metachronous disease, no progressive disease as best response to first-line treatment, the possibility of metastasectomy with curative intent and use of palliative radiotherapy were indicators for better survival. Conclusion: The prognosis of patients with metastatic leiomyosarcoma is limited and objective responses to first-line systemic therapy are rare. The treatment of metastatic leiomyosarcoma remains an unmet medical need.