Objective: Researchers are increasingly using Amazon’s Mechanical Turk (MTurk; www.mturk.com) to recruit study participants. However, the utility of MTurk for investigations of ADHD in adulthood is unknown. Method: A total of 6,526 MTurk workers (median age range = 26-35 years) completed an online screening survey assessing their diagnostic histories and symptoms of ADHD, as well as relevant demographic correlates and diagnostic comorbidity. Results: The prevalence of MTurk workers who reported being diagnosed as children and as adults, and the percentage of workers whose ADHD appeared to persist from childhood into adulthood, are consistent with those observed in "offline" samples. Relative to MTurk workers diagnosed with ADHD as adults, workers diagnosed with ADHD as children were more likely to be male and without college degrees, as well as less likely to have comorbid depression or anxiety disorders. Conclusion: Amazon’s MTurk holds promise as a recruitment tool for studying adults with ADHD.