 Antifungal therapy is widely used for individuals with Autism Spectrum Disorders ASD. The current investigation will examine the effects of fluconazole on behavioral functioning among children with ASD. This is a double-blind, randomized, placebo-controlled study of oral fluconazole in children who meet criteria for ASD. Pre- and post-treatment behavioral ratings will be used to evaluate the efficacy of fluconazole therapy. In addition, children will undergo comprehensive medical history, physical examination, and laboratory analyses. 