Effects of memantine on the spatial learning of rats were investigated using standard Morris water maze to elucidate elements of learning depending on the NMDA receptor system. Intraperitoneally applied memantine (20 mg/kg) totally abolished task acquisition. In addition, a suppression of noneffective non-spatial search strategies was impaired, that could be concluded from increases of thigmotaxis and leavings of a platform. However, a drug-free non-spatial pretraining during which the animals acquired procedural elements of the task ameliorated the memantine-induced spatial learning impairment. In memantine group with pretraining, occurrences of thigmotaxis and leavings of a platform were reduced. The obtained data suggest that the spatial learning in the Morris water maze is relatively independent of hippocampal NMDA receptors and NMDA receptor antagonists have negative effects on the acquisition of new behavioral skills and/or the suppression of ineffective strategy of behavior.