Several clinical tools have been developed to quantify the severity of withdrawal signs and symptoms exhibited by infants born to substance-using mothers. Scores from the systematic assessments are used to guide treatment of infants with moderate to severe clinical signs. This article provides an overview of published assessment tools developed for infants with neonatal abstinence syndrome. Nurses caring for infants at risk for neonatal abstinence syndrome should be knowledgeable about the tools used to evaluate these infants and guide their treatment. The ideal assessment tool should be published and include item definitions and a protocol for administering the tool. Nurses need education and training to achieve competency and interobserver reliability in the use of a selected tool. Tool-specific materials should be used to standardize training and improve accuracy in assessments. Competent and knowledgeable nurses play a critical role in improving outcomes for infants with neonatal abstinence syndrome.