Background: The COVID-19 pandemic has an impact on everyone, but autistic children and their parents are particularly vulnerable. Parenting became even more challenging with the decreased access to schools, support systems, and intervening services. Researchers must thoroughly examine the problems and needs of diverse families in their home countries, in order to recommend the most likely interventions. The aim of this study to explore the impact of COVID-19 pandemic on autistic children and their parents' stress level and functionality. Methods:  A descriptive cross-sectional study was conducted on purposive sampling of 80 autistic children and parents who used to get therapeutic services for their autistic children at three centres, in Zagazig city, Egypt. The collected data took place between June 2021 and September 2021 and included the characteristics of the autistic children and their parents, the impact of the pandemic on children and their parents' stress and functionality.  Results: The study found that more than half (52.5%) of studied parents had severe distress, 47.5% of them had severe Parent-child dysfunctional interaction, and more than two thirds (70%) of them had difficulty with child, and more than two thirds (68.8% and 71.3%), respectively, the pandemic had a negative impact on their learning and personal development. Conclusion: The COVID-19 pandemic had a major negative impact on the stress level and functioning abilities of autistic children and their parents. The paucity of resources, particularly therapeutic ones, made the challenges parents and children faced in providing for them worse.