The Internet of Things (IoT) presents itself as one of the basic pillars of the Future Internet. Such an extended network of heterogeneous ￜthingsￜ forms a global network infrastructure supported by several communication protocols where physical and virtual objects are interconnected. It is envisaged that billions of machines will be connected to the Internet, pushing the current communication technologies to their limits in terms of connectivity and performance. The wireless interconnectivity of a large number of devices in the ISM bands is a fundamental issue due to the resulting high interference environment, which degrades severely the performance and the connectivity of these devices. The Cognitive Radio technology can help mitigate the interference effect in such environments, employing smart techniques for accessing the wireless spectrum in an opportunistic manner. This paper discusses the adaptation of Cognitive Radio technology for enhancing the machine-to-machine communications, presenting the challenges and open issues for future research.