Tested a corollary of the gestalt hypothesis, that feature conjunctions are stored in transient auditory memory. The mismatch negativity (MMN), an event related potential (ERP) that is elicited by stimuli that differ from a series of preceding stimuli, was evaluated in 10 Ss (aged 21-45 yrs). A tone that differed from the preceding series of stimuli in the conjunction of 2 of its features, both present in preceding stimuli but in different combinations, was found to elicit the MMN. The data are interpreted as confirming that information about the conjunction of features is stored in the memory.