Eleven previously studied somnambulists, seven children (nine to fifteen years) and four adults (sixteen to twenty-seven years) were studied by EEG, complete physical and neurological examination, psychiatric interviews, and psychological testing. This seemed to be a heterogeneous group in terms of intelligence, socioeconomic background, family setting, and psychopathology. Physical and neurological examinations were normal except for one child who demonstrated several 'soft' signs of cerebral dysfunction. No 'somnambulistic personality' was found. There were two significant correlations: 1, a strong family history of somnambulism; 2, paroxysmal high voltage EEG activity seen just before sleepwalking in the eight subjects nine to sixteen years of age.