In recent years, there has been a growing emphasis on the mental health and social and behavioral developmental needs of very young children. In response, state administrators and local providers of early intervention and preschool programs have worked to strengthen their screening and assessment of children's social and emotional development. To meet this need, NECTAC compiled this product. This list of instruments was gathered through a review of: the infant mental health literature, states' Part C and Part B-Section 619 Web sites, screening and assessment texts, and publishers' Web sites. The screening instruments include both those that address multiple developmental domains as well as those that focus on the social-emotional developmental domain. The screening instruments are further sub-divided into those which must be administered by professionals and those that may be completed by family members or other caregivers. The information for each instrument includes a description, the age range for which the instrument was validated, the time to administer, the scoring procedure, psychometric properties, and requirements for administrators, and a link to, or address for, the publisher or source of more information.