Fatty acid synthase (FAS) is a key enzyme in the de novo biosynthesis of fatty acids. Carcinoma cells are dependent on endogenous fatty acid synthesis for growth in vitro. In a subset of human cancers, elevated FAS is associated with poor prognosis; however, the expression of FAS and the relationship between FAS and prognosis in soft tissue sarcomas (STSs) have not been studied. The objective of this study is to examine the expression of FAS in STSs and determine its relationship to clinicopathological features and prognosis.