Antianxiety effect of noncompetitive NMDA receptor antagonist MK 801 was investigated on elevated plus-maze paradigm in rats. Interactional effects of MK 801 with the specific anxiolytic agent, diazepam; the anxiogenic β- carboline agent, FG-7142 and the central BZ receptor antagonist Ro 15-1788 were explored. MK 801 (0.025-0.1 mg/kg) produced anxiolytic effect at all the doses in rats. Effect was potentiated by diazepam in rats. Both, FG-7142 and Ro 15-1788 reversed the effects of MK 801 and diazepam, when these agents were concomitantly administered. The study revealed anxiolytic profile of MK 801 and indicates that NMDA receptors can modulate the benzodiazepine receptor activity in rodents in elevated plus-maze apparatus.