Task-irrelevant stimuli are later recognized at enhanced levels providing that they had previously appeared with a task-relevant target (Dewald & Sinnett, submitted; Seitz & Watanabe, 2003, 2005). The present investigation explores this notion in the auditory sensory modality. Participants listened to a stream of auditory sounds and spoken words with the instruction to detect repetitions in only the sound stream (i.e., ignore the words). A surprise test measured recognition for the previously played words. Overall, when comparing target-aligned and non-aligned information in a later recognition task, facilitation was observed for words that had been aligned with target repetitions, despite equal presentation frequency and being irrelevant to the primary repetition task. This enhancement was mediated by the sensory modality of presentation in the surprise recognition task. Congruent auditory presentations between the exposure and recognition tasks yielded improved performance, and under cross-modal presentations the magnitude of the enhancement was greatest.