In recent years, there has been an increasing interest in clinical and research applications of virtual reality (VR). However, the adoption of this approach is still limited by the high costs of software development, lack of technical expertise among end-users, and the difficulty of adapting the contents of the virtual environments (VEs). To address these needs, we have designed and developed NeuroVR, (http://www.neurovr.org), a cost-free virtual reality platform based on open-source software components. NeuroVR allows non-expert users to easily customize a VE by using a set of pre-designed virtual scenes, and to run them in an immersive or non-immersive modality. In this paper, we provide a description of the key functional features of the platform.