Research has shown that subliminal presentation of MOMMY AND I ARE ONE (MIO) can help improve adaptive functioning. Two experiments tried to determine whether changes in mood, especially free-response mood, could help explain these findings. In one experiment, 20 men were randomly assigned to receive either a subliminal MIO or control stimulus. Results showed predicted effects on a free-response and no effects on a self-report mood measure. In the other experiment, 54 male subjects randomly received one of three subliminal stimuli. They evidenced the same pattern of mood results. Sentential semantics were shown to be relevant to the obtained results. Ascending threshold and 150 forced-choice discrimination trials demonstrated that subjects could not report stimulus content. It was concluded that MIO effects were attributable to unconscious processing of the entire message and that free-response mood may partly mediate these effects. Suggestions for future research were offered.