In this paper, one of the most important aspect of the cognitive radio i.e. spectrum sensing is considered. A new technique based on Multiple Input and Multiple Output (MIMO) antennas is proposed for spectrum sensing in cognitive radio. This paper shows the results which prove that the use of MIMO antennas increases the "Probability of detection" and decreases the "Probability of missed detection" of the target. Thus, this paper increases the chance to exploit spectrum resources more efficiently, so that spectrum scarcity problem is alleviated.