Synovial sarcoma (SS) is an uncommon soft tissue tumor occurring mainly in the periarticular region of the extremities of young adults. In this report, we describe a very rare occurrence of primary SS of the esophagus in a 72-year-old woman. Histologically, the tumor demonstrated biphasic morphologic findings associated with poorly differentiated areas. Tumor cells expressed vimentin, epithelial (EMA, CK7, AE1/3), bcl-2 and neuroectodermal (CD56, CD57, CD99) antigens. Differential diagnose included esophageal sarcomatoid carcinoma. Cytogenetic analysis confirmed the diagnosis of SS by identifying t(X;18) translocation. The literature of this very uncommon entity of the esophagus is reviewed.