BACKGROUND The purpose of the present study was to identify the prognostic factors of and to determine the most appropriate mode of treatment for uterine leiomyosarcoma. METHODS We reviewed the hospital records, including surgical notes and pathologic reports, of 21 patients with uterine leiomyosarcoma treated at Chang Gung Memorial Hospital, Kaohsiung, Taiwan, between 1987 and 1997. Univariate analysis was performed using the log-rank test. Cox regression was used to identify independent prognostic factors. RESULTS The mean follow-up time was 30 months, and the 5-year disease-free survival rate was 55%. Evaluating the correlation between clinicopathologic parameters and survival, early stage (p = 0.0002), tumor cells without necrosis (p = 0.0026), low-grade tumor (p = 0.015), absence of vascular space involvement (p = 0.006), and tumor without atypia (p = 0.016) were associated with good prognosis. However, in a multivariate analysis using the Cox model, only advanced stage (p = 0.032) and tumor necrosis (p = 0.032) were found to be independent poor prognostic factors. The 5-year disease-free survival was only 21% in patients with the presence of any one or both of these two factors. Five of 11 patients in this group had received aggressive adjuvant therapy after surgery, and none of them survived more than 19 months. CONCLUSIONS We found that patients with advanced stage or presence of tumor necrosis had an extremely poor prognosis. Adjuvant therapy seemed to play a limited role, and provided no survival benefit. Treatment for these patients should be palliative until effective therapeutic modalities prove otherwise.