This issue of "The NSDUH Report" examines the number of children living with substance-dependent or substance-abusing parents. It focuses on biological, step-, adoptive, and foster children under 18 years of age who were living with one or both parents at the time of the survey interview. All findings are based on annual averages from the combined 2002 to 2007 NSDUH data. Combined data from 2002 to 2007 indicate that over 8.3 million children under 18 years of age (11.9 percent) lived with at least one parent who was dependent on or abused alcohol or an illicit drug during the past year. Of these, almost 7.3 million (10.3 percent) lived with a parent who was dependent on or abused alcohol, and about 2.1 million (3.0 percent) lived with a parent who was dependent on or abused illicit drugs. About 5.4 million children under 18 years of age lived with a father who met the criteria for past year substance dependence or abuse, and 3.4 million lived with a mother who met the criteria. (Contains 2 figures, 1 table and 6 endnotes.)