Objective. Glutamate, an excitatory neurotransmitter in the central nervous system (CNS), may play a role in the development of anxiety. Memantine partially blocks N-methyl-D-aspartate (NMDA) receptors' glutamate channels located in the CNS. This paper evaluates memantine as an augmentation therapy for treatment of anxiety. Methods. 15 consecutive partially responding anxious patients were treated with adjunctive memantine for 10 weeks. Memantine was dosed 5-20 mg/day. Result. Memantine augmentation resulted in clinically relevant reduction in anxiety symptoms when compared to baseline. Forty percent of patients achieved remission (HAM-A ≥ 7). Memantine improved sleep quality. Mean dose was 14 mg/d (range 5-20 mg/d). Typical adverse events included nausea and headache. Conclusion. The NMDA receptor antagonist memantine may be an effective augmentation therapy in patients with treatment-resistant anxiety.