Learning is a change in behavior evoked by experience. One form of simple learning is habituation or the gradual decrease in the response to repeated extraneous stimulation. Habituation is a non-associative form of learning where the organism learns about stimuli by responding less and less with repeated stimulation or exposure to a stimulus. In this study, we tested the role of NMDA receptor activation in olfactory habituation by direct infusions of 8mM and 4mM MK-801, an NMDA antagonist, into the olfactory bulbs of adult Sprague Dawley rats during an olfactory habituation paradigm. Our results show that infusions of the NMDA antagonist MK801 at 8 mM concentration led to a general depression of the olfactory response. Olfactory habituation memory formation was blocked after infusion of a lower dosage (4 mM) of the NMDA antagonist. These results show that bulbar NMDA receptors are important for habituation of olfactory memories. From our studies, it is clear that NMDA receptors in the olfactory bulb are necessary for the formation of habituation memory, and that blocked NMDA receptors impair olfactory habituation.