We report here a case of reversible posterior leukoencephalopathy syndrome(RPLS)induced by modified FOLFOX6(mFOLFOX6). The patient was a 43-year-old woman who had sigmoid colon cancer with multiple liver metastases. Treatment with mFOLFOX6 was started. Early in the morning of day 11, the patient was transported by ambulance to the hospital due to nausea with headache, disturbed consciousness, and visual disturbance. The patient experienced sudden, severe nausea and subsequently presented generalized tonic-chronic seizures. The seizures subsided after treatment. On the evening of day 11, another episode of generalized tonic-chronic seizures occurred. Status epilepticus developed and tracheal intubation was performed for airway protection. Cranial MRI showed increased signal intensity in both occipital lobes, centered on the boundary between the gray and white matter on FLAIR images. Her condition stabilized with no seizure recurrence following intubation. Although hypertension was present on admission to the emergency room, blood pressure gradually fell to within the normal range without antihypertensive treatment. She was extubated on day 18. There were no neurologic sequelae. Cranial MRI on day 40 showed that the increased intensity in both occipital lobes had almost disappeared. Because the patient's condition was characterized by a reversible central nervous system disorder, RPLS was diagnosed.