Typically the sensory information entering our ears is much more than we can deal with. Selective attention limits processing so we can handle the vast amount of information that we encounter daily. Actively selecting a subset of sensory information has been shown to modify the input at an early processing stage, generally seen as an enhancement of the neural activity for the relevant features of the input. In this talk I provide evidence of another type of attention effect on neural activity, affecting the representation of successive sounds in memory. Event-related brain potentials were used to identify the timing of various cognitive processes and, in combination with measures of subject's perception of the sounds, to assess the stage at which attention interacted with sensory input in perception. In one study, attention modified the organization and storage of sound in memory, reflected by the absence or presence of specific ERP components. In another study attention increased accuracy for discriminating stimulus information but did not change the way the information was represented in auditory memory. These data suggest that there is more than one mechanism of auditory attention operating at different processing stages depending on the listener's task, and further, supports the notion that attention interacts with stimulus-driven processes to facilitate behavioral goals.