The study seeks to analyze the needs of the children diagnosed with autism spectrum disorder (ASD) and identify the requirements for autism-friendly environments. It aims to develop a design guideline that can enhance the quality of spaces for users by organizing an existing building. Therefore, the spatial needs of individuals with ADC were investigated across different criteria including accessibility, safety and security, clarity, predictability and proportionality, spatial organization and flexibility in space arrangement and building design, spatial sequencing, transition spaces and escape areas; as well as surfaces, textures, acoustics, light, color, and sensory integration activities. During the literature review phase, Google Scholar was utilized, and relevant studies were selected by reading the titles, abstracts, and full texts. The criteria outlined in these studies were analyzed in a source and criteria table, identifying common headings. In addition, a checklist that includes these common headings were prepared. Using this checklist, the structure of a kindergarten in Istanbul accommodating children with autism was examined by taking photos and recording videos and suggestions have been presented. The study revealed that Başakşehir Kiraz Çiçeği Kindergarten mostly meets the criteria of an autism-friendly environment for children.