This investigation compared self-talk use in five preschool autistic children (ages 57 to 86 months) and in matched chronological age and mental age peer groups. Videotape recordings of the children during free play with and without an adult were coded for the following self-talk categories: (1) private, mastery speech; (2) stereotypic repetitions; (3) word play; (4) self-regulative speech; (5) utterances; and (6) mouthing of words. All three groups exhibited fewer instances of self-talk in the presence of adults than without an adult. The autistic children demonstrated a similar pattern of self-talk with adults as did their control peers. Autistic children showed less consistency in behaviors between the adult present and adult absent situation than did controls; this was not felt to reflect their lack of response to adults in their environment, but rather to the high production of utterances and private mastery talk when they were not with an adult. (Contains six figures/tables.) (JDD)