Endometrial Stromal Sarcoma (ESS) is a rare uterine malignancy. The annual incidence of ESS has been reported as 1 - 2 per million women. In the general population approximately 10 percent of cancer patients may develop a second primary cancer. Synchronous multiple primary tumors constitute only 20% of all multiple primary tumors, and by definition, occur within a period of two month. This case report is presented to document the occurrence of ESS as a “Synchronous Multiple Primary Tumor”, which is an extremely rare event. Previously only one case report has documented such an occurrence. The literature is also briefly reviewed. This case underlines the requirement of a thorough initial evaluation for a patient with a gynecological malignancy and a regular follow-up. Follow-up includes patient education regarding symptoms of any recurrence, physical examination repeated at 6 - 12 monthly interval, along with imaging studies when indicated.