Neonatal abstinence syndrome (NAS) is a postnatal drug withdrawal syndrome that occurs primarily among opioid-exposed infants shortly after birth, often manifested by central nervous system irritability, autonomic overreactivity, and gastrointestinal tract dysfunction (1). During 2000-2012, the incidence of NAS in the United States significantly increased (2,3). Several recent publications have provided national estimates of NAS (2,3); however, data describing incidence at the state level are limited. CDC examined state trends in NAS incidence using all-payer, hospital inpatient delivery discharges compiled in the State Inpatient Databases of the Healthcare Cost and Utilization Project (HCUP) during 1999-2013. Among 28 states with publicly available data in HCUP during 1999-2013, the overall NAS incidence increased 300%, from 1.5 per 1,000 hospital births in 1999, to 6.0 per 1,000 hospital births in 2013. During the study period, significant increases in NAS incidence occurred in 25 of 27 states with at least 3 years of data, with annual incidence rate changes ranging from 0.05 (Hawaii) to 3.6 (Vermont) per 1,000 births. In 2013, NAS incidence ranged from 0.7 cases per 1,000 hospital births (Hawaii) to 33.4 cases per 1,000 hospital births (West Virginia). The findings underscore the importance of state-based public health programs to prevent unnecessary opioid use and to treat substance use disorders during pregnancy, as well as decrease the incidence of NAS.