Cyclins are a group of proteins that act as activators to cyclin-dependent kinases and are required for normal cell cycle transitions. Cyclin A is involved in the transitions between G1 to S and G2 to M. Its deregulation has been linked to a number of neoplasms, including endometrial cancer. The prognostic significance of cyclin A expression seems to be cancer-specific, and current knowledge on its impact on survival of endometrial cancer is limited. This study aimed to investigate the effect of cyclin A expression on cancer-specific survival and its correlation with conventional prognostic factors in endometrioid adenocarcinoma. Biopsies obtained from 211 patients were immunohistochemically stained for cyclin A and differences in expression analyzed at the Oulu University Hospital. Patients were divided into two groups utilizing the ROC curve. Further survival analyses were carried out between these two groups. In this study, we show that cyclin A expression correlates with tumor grade and FIGO stage. We also show that cyclin A is an independent prognostic factor in endometrioid adenocarcinoma. Whether cyclin A plays a role in tumorigenesis or merely is a marker of increased proliferation requires further studies.