National Technical Assistance and Dissemination Center for Children and Youth who are Deaf-Blind and its predecessors, The National Technical Assistance Consortium for Children and Youth who are Deaf-Blind (NTAC) and the Teaching Research Assistance to Children Experiencing Sensory Impairments (TRACES) project, has been conducting an annual National Child Count of Children and Youth who are Deaf-Blind since 1986. This national child count, commonly referred to as the "Census", is conducted on December 1st of each year to supplement OSEP's federal Child Count, which includes children as deaf-blind when deaf-blindness represents their only disability. Since the majority of children with deaf-blindness do have additional disabilities they are not included in the OSEP Child Count as deaf-blind. In contrast to OSEP's December 1 count, the Census data are collected for children with deaf-blindness in isolation, as well as those with additional disabilities. The Census represents the first, longest running, and most comprehensive registry of infants, young children, and students who are deaf-blind. Through the years, the collection of deaf-blind specific child count data and its ensuing analysis has provided valuable information. It has assisted state and national deaf-blind technical assistance projects in the design of their services, as well as in meeting the requirements of their various funding agencies. The Census has grown throughout the years and now represents a comprehensive data set including: (1) The specific number and ages of the infants, young children, and students (birth through 21) who are deaf-blind throughout the country; (2) The primary etiology of their deaf-blindness; (3) Any additional disabilities they may have; (4) The type and degree of their hearing and vision loss; (5) Their ethnicity; (6) Their IDEA classification, special education status and placement; and (7) Their living setting.