Objective: Parents of children with autism spectrum disorders (ASDs) often try a variety of treatments for their children, including complementary and alternative medicine (CAM). The objective of this study was to improve understanding of the frequency of CAM use by parents for their children with autism and to quantify the parents' perceived effectiveness of various CAM therapies in mitigating the health and functioning problems associated with autism. Methods: Parents in southeastern Virginia were recruited for study participation from local autism organizations and a clinical practice where a large proportion of the patients are children with autism. Parents completed an online survey and answered questions about CAM use for their children with autism, and they rated the perceived effectiveness of each therapy. Results: Of 194 parents surveyed, 80.9% reported that they had tried some form of CAM for their child with autism. Among CAM users, the most frequently used therapies were multivitamins (58.6%), the gluten-free casein-free diet (54.8%), and methyl B-12 injections (54.1%). The CAM therapies that received the highest average rating of effectiveness were sensory integration therapy, melatonin, and off-label use of prescription antifungal medications. Conclusion: CAM therapies were frequently used in this population, and many were perceived to be effective in helping to ease some of the health challenges associated with autism. CAM therapies for the autism population should be further studied in well-controlled clinical research settings to provide safety and efficacy data on treatments, as well as validated treatment options for those with ASD.