Background and Aims:Attention Deficit/Hyperactivity Disorder (ADHD) is clearly over represented among patients with drug addiction. Deficits in working memory (WM) are thought to be of central importance for ADHD. Previous studies indicate that WM can be improved by training.In this pilot study we have examined if training of WM in adult patients with ADHD and a history of severe drug abuse would be possible to apply in a clinical setting. In addition, we hypothesized that the training would improve WM in this group.Patients and Methods:Subjects: Nine patients with ADHD and a history of drug abuse were recruited. The age range was 21-52. One patient was addicted to alcohol, one to cannabis and seven patients to amphetamine. All patients had been drug-free more than two months prior to inclusion. Outcome measures: WM was assessed using four different tasks. The Self Rating Scale (CFQ) was used to score symptoms of cognitive failures in daily life. Training procedure: The treatment consisted of performing WM tasks implemented in a computer program (RoboMemo®).Results:Eight patients completed the treatment and remained drug-free during the training. There was a clear improvement in two WM test. Seven patients reported a subjective improvement as rated in CFQ.Conclusion:This pilot study shows that computerized training of working memory can be performed in a clinical setting of adults with ADHD and drug addiction. The improvement support that patients with drug-addiction may have the same plasticity in the brain that non-addictive patients show.