Generalized anxiety disorder (GAD) is a psychiatric disorder characterized by a constant and unspecific anxiety that interferes with daily-life activities. Together with the cognitive-behavioural treatments, relaxation represents a useful approach for the treatment of GAD, but it has the limitation that it is hard to be learned. To overcome this limitation we propose the use of biofeedback enhanced virtual reality (VR) to facilitate the relaxation process. The VR relaxation experience will be strengthened by the use of a mobile phone able to track and visualize, in an outpatient setting too, the physiological data of the patients. To test this concept, we planned a randomized controlled trial (NCT00602212), including three groups of 15 patients each (for a total of 75 patients): (1) the VR group, (2) the non-VR group and (3) the waiting list (WL) group. This controlled trial will be able to evaluate the effects of the use of VR in relaxation while preserving the benefits of randomization to reduce bias.