From 2004 to 2014, the incidence of neonatal abstinence syndrome (NAS) in the United States increased 433%, from 1.5 to 8.0 per 1,000 hospital births. The latest national data from 2014 indicate that one baby was born with signs of NAS every 15 minutes in the United States (1). NAS is a drug withdrawal syndrome that most commonly occurs among infants after in utero exposure to opioids, although other substances have also been associated with NAS. Prenatal opioid exposure has also been associated with poor fetal growth, preterm birth, stillbirth, and possible specific birth defects (2-5). NAS surveillance has often depended on hospital discharge data, which historically underestimate the incidence of NAS and are not available in real time, thus limiting states' ability to quickly direct public health resources (6,7). This evaluation focused on six states with state laws implementing required NAS case reporting for public health surveillance during 2013-2017 and reviews implementation of the laws, state officials' reports of data quality before and after laws were passed, and advantages and challenges of legally mandating NAS reporting for public health surveillance in the absence of a national case definition. Using standardized search terms in an online legal research database, laws in six states mandating reporting of NAS from medical facilities to state health departments (SHDs) or from SHDs to a state legislative body were identified. SHD officials in these six states completed a questionnaire followed by a semistructured telephone interview to clarify open-text responses from the questionnaire. Variability was found in the type and number of surveillance data elements reported and in how states used NAS surveillance data. Following implementation, five states with identified laws reported receiving NAS case reports within 30 days of diagnosis. Mandated NAS case reporting allowed SHDs to quantify the incidence of NAS in their states and to inform programs and services. This information might be useful to states considering implementing mandatory NAS surveillance.