The increasing recognition of early childhood mental health issues and increased public interest in prevention both highlight the importance of developing new methodologies to assess the emotional and developmental needs of young children. The Early Childhood Service Intensity Instrument (ECSII), developed by the AACAP Work Group on Community-Based Systems of Care, is a clinician-rated scale to assess service intensity need for young children ages 0-5. It is a companion tool to the Child and Adolescent Service Intensity Instrument (CASII). The ECSII provides a common language that can be used by multiple service agencies providing care to young children. It also provides guidance for comprehensive service planning. This Workshop describes the ECSII in detail, including how to administer and score the ECSII. Its psychometric properties are also reviewed. Attendees receive an ECSII manual and practice scoring a clinical vignette.