Antennas that are able to direct the transmitted and received signals' energy are of great interest for future wireless communication systems. The directivity implies reduced transmit power and interference, and hence potential for increased capacity. In this paper we present the results of measurement trails and FEMLAB simulations of the Bluetooth link employing different antennas in NLOS for indoor office environments. The results show the potential improvement in system performance gained from the use of directive antennas and the great dependency of the results on the antenna parameters (gain and efficiency) and the overall impact on the quality and coverage of the Bluetooth link. The results are also expected to provide an insight into the performance of antennas for other indoor wireless technologies such as ultra wideband (UWB) radio communications where the antenna impact and design is expected to be even more critical.