This report describes the clinico-pathological features of acute lymphocytic meningoencephalitis (ALME) of a patient with a long clinical course of 24 months. The patient rapidly developed a confusional state, occasionally with stupor, various involuntary movements and generalized convulsions followed by fever and headache at the age of 29. Clinical symptoms, except fever and convulsions, had not distinctly improved throughout the clinical course, and cortical atrophy on CT and MR gradually progressed. SPECT revealed a low blood perfusion in the cerebral cortices. Neuropathologically, inflammatory findings were very mild, but nerve cells degenerated prominently. From these clinicopathological findings, it is suggested that chronic degenerative changes followed an acute inflammatory phase.