Parents of children newly diagnosed with Autism Spectrum Disorders (ASD) are faced with the daunting task of choosing from numerous autism interventions. At the time this research project began, little was understood about how parents made decisions for their child following the diagnosis. A few groups and organisations, in Australia and overseas, have designed and disseminated resources in various formats to help parents with decision making, but none had been evaluated in a clinical trial that tested the effectiveness of the resource in facilitating this process. Based on a review of the literature, and with consideration for the gap in research on this topic, a mixed methodology project was designed. The project incorporated five studies aiming to: 1) develop an understanding of the information that parents of children with ASD currently use to make intervention decisions, and their information preferences; 2) develop an understanding of parents’ decision making processes; 3) evaluate the quality of information most commonly accessed by parents, particularly web-based information; 4) determine how best to help parents understand what interventions are available and how they are classified; and 5) develop and conduct a pilot evaluation of the effectiveness of a decision aid. Study 1 was a cross sectional survey of Autism Advisors, and parents across Australia who were accessing the Helping Children With Autism (HCWA) funding package. The study aimed to obtain a better understanding of how parents made decisions about autism interventions, and which resources they accessed to obtain intervention information. Participants were Autism Advisors (n=13) and parents (n=113) attending initial consultations with an Autism Advisor. After determining that parents frequently accessed the Internet for ASD intervention information, it was considered important to investigate the quality of information parents were likely to be finding. Study 2 analysed the quality of health information in a sample of autism-related websites using a valid and reliable health information evaluation tool called DISCERN. This study found that websites were of variable quality and frequently lacked references to research evidence. Study 3 involved conducting focus groups and individual interviews with parents (n = 23) whose children were aged under 18 years and diagnosed with an ASD. The aim was to further investigate parents’ decision making processes and further explore the various formats and sources of information used. This study revealed that parents engaged in both a pragmatic and emotional journey and gained confidence over time in relation to their decision making regarding interventions for their child. Study 4 involved developing a web-based decision aid informed by the results of the first three studies, and with consideration for the literature on shared decision making, health literacy and patient education. The resource aimed to assist parents to make better-informed decisions about autism interventions, with consideration of research evidence, and with the view to promoting shared decision making. Study 5 was a pilot randomised controlled trial (RCT), which aimed to determine the effectiveness of the decision aid. Participants were parents (n= 81) (all mothers) of children newly diagnosed with autism within 12 months prior to commencing the trial. The primary outcome was decisional conflict measured using the Decisional Conflict Scale (DCS). Secondary outcome measures were confidence about decision making and parenting sense of competence. Parents in the intervention group were provided with access to the web-based decision aid. Parents in the control group received usual care. Data were analysed for 71 participants, following the loss of 10 participants at follow-up. The baseline mean total Decisional Conflict scores for both groups fell within the low to moderate range of decisional conflict. Follow-up scores on this measure were lower for both groups, indicating decisional conflict reduced over time, although the difference between the groups at follow-up was not significant. There were also no significant differences between the groups at follow-up in any of the Decisional Conflict Scale (DCS) subscales, the Parenting Sense of Competency (PSOC) total or subscales, or the measure of confidence. There was a small increase in the mean score for confidence with making decisions about ASD interventions for both groups. This is consistent with existing research that suggests that as parents have the opportunity to search for information about autism, become more familiar with their child’s condition, and adjust to the diagnosis, they also report feeling more confident with making decisions related to their child’s intervention needs. Increased confidence with decision making however, may not necessarily mean that parents better understand the intervention options available, including risks and benefits, likely outcomes, or available research evidence. Parents’ information needs change over time, with more prescriptive or instructive information preferred immediately post-diagnosis. Further research is required to explore alternative methods of communicating research evidence to parents of children newly diagnosed with ASD.