The present study examined the prevalence of Swedish children living with at least one parent whom has a substance use disorder (SUD), i.e. either an alcohol use disorder (AUD) or a drug use disorder (DUD).A 2013 cross-sectional survey of a nationally representative sample (n = 15,576) of the Swedish adult population 17-84 years of age was used. The response rate was 59.3%. SUDs were measured using selected parts of the Mini International Neuropsychiatric Interview (MINI), derived from the 4th edition of the diagnostic and statistical manual of mental disorders (DSM-IV). In total, 3778 parents with 7448 children under the age of 18 years participated.The proportion of children whose parent had a SUD was 4.6%, implying that around 90,000 children in Sweden experience this situation. Having a parent with an AUD was most common (3.7%), while 0.7% and 0.2% had a parent with a DUD and both (AUD plus DUD), respectively.Our results showed that a substantial number of children in Sweden have parents with a SUD and that it is important to consider both alcohol and drugs, when estimating the size of this group. Our findings call for further strategies to support these children and their families.