The simultaneous processing of auditorily and visually presented messages was examined in three experiments. Subjects searched lists of words for a target word while processing auditorily presented information. Across conditions, subjects searched for (a) target words in a list of words presented auditorily, (b) the same target words in lists presented visually, (c) a member of a taxonomic category in a visually presented list, and (d) a rhyme in a list of words presented visually. The level of processing of a simultaneous auditory message varied across experiments. In experiment 1, subjects shadowed lists of digits. In Experiment 2, subjects reported the antonym of each word in a list. In Experiment 3, subjects named the taxonomic category of each word in a list. In all three experiments, subject had high detection rates for target words presented visually and for category targets but low detection rates for target words presented auditorily and for rhyme targets. These results suggest that processing the semantic properties, but not the acoustic properties, of words presented to the visual modality is independent of simultaneous processing in the auditory modality. Implication for models of selective attention are discussed.