Mottephobia is an anxiety disorder revolving around an extreme, persistent and irrational fear of moths and butterflies leading sufferers to panic attacks. This study presents an ARET (Augmented Reality Exposure Therapy) environment aimed to reduce mottephobia symptoms by progressive desensitization. The architecture described is designed to provide a greater and deeper level of interaction between the sufferer and the object of its fears. To this aim the system exploits an inertial ultrasonic-based tracking system to capture the user’s head and wrists positions/orientations within the virtual therapy room, while a couple of instrumented gloves capture fingers’ motion. A parametric moth behavioral engine allows the expert monitoring the therapy session to control many aspects of the virtual insects augmenting the real scene as well as their interaction with the sufferer.