OBJECTIVES: This analysis considers the impact of ADHD in adults on 1) labor force status, and 2) workplace absenteeism and presenteeism in the US. METHODS: Data from the 2009 US National Health and Wellness Survey (NHWS) were used to identify all those in the labor force 18 to 49 years of age with a diagnosis of attention deficit disorder (ADD) or ADHD.  The analysis was in two stages: 1) an evaluation of the prevalence of adult ADHD (n = 40,428), and 2) the estimation of  logistic regressions to assess the contribution of unmedicated/medicated ADHD to labor force status and the estimation of ordered probit regressions (n = 25,862) to assess the contribution of unmedicated/medicated ADHD to absenteeism and presenteeism. Additional variables that are considered are socio-demographic status and health risk factors, together with the Charlson Comorbidity Index (CCI). RESULTS: An estimated 2.7% had diagnosed ADHD. This had a significant negative impact on labor force participation (odds ratio 0.817), although medicated ADHD had no impact. . The presence of unmedicated ADHD and medicated ADHD were, however, significant at the 1% level in both the absenteeism and presenteeism models. Odds ratios in the absenteeism model were 4.79 for those with unmedicated ADHD and 3.27 for those with medicated ADHD. These were of a similar magnitude to odds ratios for health risk factors (obesity 3.40 and morbid obesity 6.34) but less than the CCI odds ratio 17.43. In the presenteeism model, the odds ratios were also significant at the 1% level at 8.07 for medicated and 6.99 for unmedicated ADHD. CONCLUSIONS: The presence of unmedicated, ADHD in adults has a negative impact on labor force participation in the US. Irrespective of whether or not the ADHD is medicated, its presence also has a significant impact on increased absenteeism and presenteeism.