This report describes a project that uses existing data sets to describe the population of students with significant cognitive disabilities and known or suspected dual sensory loss. It includes students with suspected dual sensory loss because students with significant cognitive disabilities are reported to have unidentified sensory loss (Erickson & Quick, 2017). It is based on data collection from the 2018 National Child Count of Children and Youth Who Are Deaf-Blind (Child Count) and the 2017-2018 First Contact survey. The Child Count is updated annually by every state deaf-blind project to provide information about new children who were identified with dual sensory loss over the course of the year, update or confirm information on previously identified children, and determine those who have exited special education or are no longer eligible to receive state project services. Data on the First Contact survey describe teacher-reported characteristics and skills of their students with significant cognitive disabilities who were enrolled to take the Dynamic Learning Maps® (DLM®) alternate assessments. Both data sets contained information about students' disabilities, sensory characteristics, educational experiences, and use of assistive technology. Each data set also contained unique information (e.g., academic skills for the First Contact survey, intervener services for Child Count data). Analyses are based on students in 17 states that administered DLM alternate assessments in 2017-2018. The findings are organized according to three broad research questions: (1) What proportion of students with significant cognitive disabilities have dual sensory loss? What are the characteristics of students with dual sensory loss and significant cognitive disabilities? (2) How are students with significant cognitive disabilities and cortical visual impairment different from students with significant cognitive disabilities and other visual impairments? (3) What do the Child Count and First Contact survey data sets indicate about the prevalence of significant cognitive disability and dual sensory loss in the school-aged population?