The present article reviews whether available efficacy and safety data support the pharmacological treatment of adult attention-deficit/hyperactivity disorder (ADHD) in patients with concurrent substance use disorders (SUD). Arguments for and against treating adult ADHD with active SUD are discussed. Findings from 19 large open studies and controlled clinical trials show that the use of atomoxetine or extended-release methylphenidate formulations, together with psychological therapy, yield promising though inconclusive results about short term efficacy of these drugs in the treatment of adult ADHD in patients with SUD and no other severe mental disorders. However, the efficacy of these drugs is scant or lacking for treating concurrent SUD. No serious safety issues have been associated with these drugs in patients with co-morbid SUD-ADHD, given their low risk of abuse and favourable side effect and drug–drug interaction profile. The decision to treat adult ADHD in the context of active SUD depends on various factors, some directly related to SUD-ADHD co-morbidity (e.g. degree of diagnostic uncertainty for ADHD) and other factors related to the clinical expertise of the medical staff and availability of adequate resources (e.g. the means to monitor compliance with pharmacological treatment). Our recommendation is that clinical decisions be individualized and based on a careful analysis of the advantages and disadvantages of pharmacological treatment for ADHD on a case-by-case basis in the context of active SUD.