An autopsy case of 23-years-old man with Prader-Labhart-Willi syndrome (P-L-W syndrome), who had died by acute renal failure due to burn injury, was reported. P-L-W syndrome was constituted by hypotonia, hypogonadism, hypomentia, obesity and other minor anomalies, however, CNS anomaly had not been reported. The patient sat at 3 years of age, walked at 4 years old, began to utter single words at 3-4 years, and he began to obese at 4 years of age. He fulfilled the condition of P-L-W syndrome mentioned above. On his age 15, laboratory findings on admission revealed remarkable diabetic pattern by oral glucose tolerance test and intelligence quotient was 28, and the other laboratory findings were within normal limit. During his clinical history, complications of diabetes mellitus, such as diabetic retinopathy and neuropathy, were aggrevated, and upstanding and gait were impossible at 20 years of age. On his age 23, he suffered from burn injury at left lower extremity and he fell in acute renal insufficiency. Five autopsy cases of P-L-W syndrome have been reported so far, however, CNS anomaly has not been observed. Following anomalies in our case was recognized, such as shortness of the frontal lobe, partial micropolygyria of the dentate nucleus, heterotopia of the inferior olivary nucleus, ectopia of Purkinje cell in the molecular layer, heterotopia of middle sized neuron in the deep white matter of the cerebellum and large number of residual nerve cells in the cerebral subcortical white matter.(ABSTRACT TRUNCATED AT 250 WORDS)