In June 1999, a 50-year-old Japanese woman underwent a liver transplant and was started on tacrolimus hydrate. A routine gynecologic examination at that time was unremarkable. In December 2001, the patient was found to suffer from endometrial adenocarcinoma and total abdominal hysterectomy with adnexa was carried out. No significant changes in liver function were observed. However, because fever in the patient of up to 38.5 degrees C continued, the volume of the tacrolimus hydrate was reduced, and then stopped completely. The patient's fever decreased to approximately 36.5 degrees C and she was discharged on the 18th postoperative day. The present case is the first report of endometrial adenocarcinoma in a patient after liver transplantation.