Endocervical adenocarcinoma with retrograde mucosal spreading to the ovary is extremely rare. Although we could not completely exclude the possibility of lymphovascular spreading, we performed a detailed sectioning study to identify a possible retrograde route, including the fallopian tube, which has been ignored in previous studies. This retrograde route is identical to that found in endometriosis-associated carcinoma of the ovary. In addition, the histopathologic morphology, immunoprofile, and human papillomavirus genotyping all indicated retrograde metastasis of the same tumor cells.