Autism is the fastest growing disability ever. With the growth comes a lot of questions as to the etiologies and treatment of this condition, often putting parents, schools, and traditional medical personnel at odds with what treatments have efficacy. As the popularity of alternative treatments increase, so does the need for research. Hyperbaric oxygen therapy is one alternative treatment parents are seeking for their child with autism. When one looks at the science behind hyperbaric oxygen therapy and the physical condition of a child with autism the rationale behind the treatment becomes clear. Research has shown that children with autism have decreased cerebral blood flow, neurological and gastrointestinal inflammation, reduction of purkinje cells, poor immune systems, increase of heavy metals, and deficits with their myelination. When these conditions are compared to the benefits one receives in hyperbarics a correlation is noted, and an understanding of why a child functioning improves. This research was a study of five children with school diagnosis of autism that were doing hyperbaric oxygen therapy. Both the parents and the child's teacher filled out a pre and post evaluation of the child using ATEC evaluation tool. The evaluation tool assessed improvements in the area of speech/language/communication, sociability, sensory/cognitive awareness, health/physical/behavior of a child with autism. The results were assessed with the SPSS (Statistical Package for the Social Sciences Personal Computer) software using t-test with Paired Samples Statistics data analysis to compare the pretest and posttest scores. All areas showed improvements. In speech/language/communication the parents reported a 6.33 percentage of improvements and the teachers reported a 10.34 percentage of improvements. In sociability the parents reported a 10.53 percentage of improvements and the teachers reported a 3.96 percentage of improvements. In sensory/cognitive awareness the parents reported a 4.11 percentage of improvements and the teachers reported a 14.29 percentage of improvements. Lastly, in health/physical/behavior the parents reported a 17.61 percentage of improvements and the teachers reported a 10.22 percentage of improvements. Overall, the study concluded that further research with a larger sample size is warranted to see if hyperbaric oxygen therapy can help benefit children with autism. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]