To examine the influence of undocumented immigration in the United States on 4 different metrics of drug and alcohol problems: drug arrests, drug overdose fatalities, driving under the influence (DUI) arrests, and DUI deaths.We combined newly developed state-level estimates of the undocumented population between 1990 and 2014 from the Center for Migration Studies with arrest data from the Federal Bureau of Investigation Uniform Crime Reports and fatality information from the Fatality Analysis Reporting System and the Centers for Disease Control and Prevention Underlying Cause of Death database. We used fixed-effects regression models to examine the longitudinal association between increased undocumented immigration and drug problems and drunk driving.Increased undocumented immigration was significantly associated with reductions in drug arrests, drug overdose deaths, and DUI arrests, net of other factors. There was no significant relationship between increased undocumented immigration and DUI deaths.This study provides evidence that undocumented immigration has not increased the prevalence of drug or alcohol problems, but may be associated with reductions in these public health concerns.