Purpose: This brief research report presents findings from a US national household survey on the number and percentage of parents with mental illness. Methods: Using combined annual data from the 2008-2014 National Survey on Drug Use and Health, parents were defined as having children in the household from birth to 18 years. Prediction models developed in an earlier clinical study using a National Survey on Drug Use and Health subsample were used to estimate serious mental illness (SMI). Results: A total of 2.7 million parents (3.8%) had a SMI in the past year and 12.8 million parents (18.2%) had any mental illness in the past year. Mental illness was more common among mothers than fathers and least common among Asians compared with other races. SMI was less prevalent in parents who were aged 50 years and older compared with younger age groups. Conclusions: The burden of mental illness in parents is high in the United States, especially among mothers. Physicians who treat parents should routinely screen for mental illness and discuss its implications for parenting. (C) 2016 Elsevier Inc. All rights reserved.