Attention-deficit hyperactivity disorder (ADHD) is a common disorder in children that frequently persists into adulthood. Studies have found that substance use disorders (SUD) are seen more commonly in those with ADHD than the general population. Although treatment with stimulant medications has been shown to be effective for individuals with ADHD, concern about the use of these agents in this population persists. This review article highlights the research in this area with a focus on the treatment of individuals who present with concomitant ADHD and SUD.Although stimulants can be abused, studies have shown that adolescents who are prescribed stimulants for ADHD have lower rates of SUD than those who are not treated with stimulants.It may be particularly difficult to evaluate adults for the diagnosis of ADHD when SUD is a co-morbid factor. Studies show that 20–30% of adults presenting with SUD have concomitant ADHD and approximately 20–40% of adults with ADHD have histories of SUD. Therefore, it is critical to perform careful diagnostic interviews to discern if patients have either or both of these disorders. Many clinical experts suggest that adults with ADHD and active SUD be treated for the SUD until a period of sobriety persists prior to initiation of specific treatment for ADHD. Since individuals with ADHD and active SUD are more likely to have more severe SUD and a worse prognosis, this approach may not serve many patients, as they relapse prior to obtaining ADHD treatment. Therefore, research has been directed towards determining if the treatment of ADHD with stimulant medications can be safe and effective for the individual with active SUD and concomitant ADHD. An initial trial of methylphenidate in a population of adults with active cocaine dependence and ADHD indicates that this is the case.Individuals with ADHD and SUD can present difficult diagnostic and therapeutic challenges. It appears that the most effective treatment option is to create a programme that uses the most effective treatment modalities available, including both behavioural and medical therapies, along with close supervision and monitoring. Newer  medical  treatment  options  of  long-acting  stimulants and non-stimulants (e.g. atomoxetine) offer effective treatment with a lower risk of abuse potential.