In this paper we investigate the use of smart antennas in MANET (Mobile Adhoc Networks) and we propose a novel MAC protocol called BMAC (Beamformed MAC) to support their benefits in obtaining higher efficiency, especially interference suppression and alleviating different problems that can appear when using directivity. Although the use of smart antenna may lead to deafness and different instances of hidden problems, increased network capacity can be obtained if a sophisticated MAC protocol is designed. The BMAC is designed to increase the throughput and to provide better quality of service.