This guidance document has been developed to assist school district personnel and families in becoming familiar with the wide range of characteristics and abilities of their students with an autism spectrum disorder (ASD) and in applying Colorado's new eligibility category of Autism Spectrum Disorder (ASD) to identify students eligible for special education services. Schools have experienced a steady increase in the number of students with autism spectrum disorder over the past 10 years. In 2012 the Center for Disease Control (CDC) estimated that about 1 in 88 young children have an ASD. The information in these guidelines may be used to guide the process of identifying students with ASD and developing appropriate programming, supports and services.