Many different factors which may affect the prognosis of the soft tissue sarcomas have been reported by many authors ; Generally, tumor size, histologic type, surgical margin, and multi modality therapy therapy as the prognostic factors were reported. The objectives of this retrospective study of soft tissue sarcomas are : 1) to define more clearly prognostic variables that have significant predictive value for disease-free and overall survival ; and 2) to evaluate tumor histologic grade based upon extent of tumor necrosis as a means of stratifying more aggressive soft tissue sarcomas(grade II & III) of the extremities. We treated 94 patients who had soft tissue sarcoma of the extremities and trunk from May 1984 to September 1994(average duration of follow-up was 5 years ranging from 2 months to 10 years) and evaluated the prognostic factors of the soft tissue sarcomas; age, sex, depth, size, location, histologic type and grade, stage, therapy modality, surgical margin, local recurrence and distant metastasis. The results were as follows. 1. The patients with poorer prognosis were over the age of fifty, whose mass was deeply located, size of the mass was over 10cm in diameter, grade III in histology, who had local recurrence, metastasis, and received only surgery. 2. Among these prognostic factors, the most significant prognostic factor was histologic grade base upon extent of tumor necrosis.