The purpose of this study was to evaluate synchronous multiple primary neoplasms of gynecologic origin in terms of clinical features, diagnosis, treatment, and relapse. Seven patients treated from 2012 to 2017 were studied; five of whom had synchronous multiple primary neoplasms associated with endometrial cancer. Two patients recurred and additional chemotherapy was performed. Synchronous multiple primary neoplasms have a better prognosis than single metastatic tumors, but they should be followed up carefully, as they tend to recur in the latter half of treatment. The authors herein report these seven cases along with a brief review of the literature.