Human and non-human primate research has shown that pathological processes affecting the temporal lobe, particularly the amygdala and hippocampus, are related to the development of the autistic syndrome. This case report describes a young male child with left temporal oligodendroglioma, who demonstrated a constellation of autistic behaviors meeting DSM-III-R criteria for pervasive developmental disorder. Abnormalities in social interaction, affective expression and communication were particularly evident. Some of the symptoms improved after tumor resection, while other signs of qualitative abnormalities in development emerged or persisted. This case adds evidence to the hypothesis that damage to mesial-temporal structures at an early developmental period may lead to the autistic syndrome.