Cognitive Radio (CR) is a regulated technique for opportunistic access of idle resources and it is expected that the golden service of spectrum sensing is to be achieved via the robust sensing technique to sense the unused spectrum in an opportunistic manner. In this paper, we propose multiple energy detectors (MED) utilising adaptive double-threshold (ADT) for spectrum sensing. In the present framework of CR networks, each CR node is equipped with MED and each energy detector with single antenna. Numerical results show that it improves detection performance at very low signal-to-noise ratio (SNR), and overcomes sensing failure problem. Further, the scheme was analysed in conjunction with cooperative spectrum sensing (CSS), where each CR users employ selection combining (SC) scheme to take global decision by MED with adaptive double-threshold (MED_ADT). It is further found that this arrangement improves detection performance around 6.3% as compared to hierarchical with quantisation method at –10 dB SNR, under the case when a small number of sensing nodes are used in spectrum sensing.