Paraneoplastic limbic encephalitis (PLE) is a remote, nonmetastatic complication of carcinoma. Neuropsychiatric symptoms usually predate the diagnosis of cancer by 3 months to 6 years and very rarely the symptoms develop after the diagnosis of malignancy. We report the first case of limbic encephalitis associated with an immature ovarian teratoma. Within the month following the diagnosis of the tumor with pathologic stage Ia, somewhat acutely she developed neuropsychiatric symptoms that was exclusively a limbic disorder with impairments in almost every realm of limbic function. This case may show us that it is important to recognize the neuropsychiatric symptoms of PLE as the first manifestation of a very small malignant ovarian tumor and to aggressively try to identify the underlying cancer.