Attention-deficit/hyperactivity disorder (ADHD) is a neuro-behavioural disorder that presents frequently in paediatric and mental health settings. Children with ADHD present with symptoms of hyperactivity, inattention, distractibility and impulsivity. The purpose of this paper is to provide clinicians with a summary of contemporary issues relevant to their clinical understanding, assessment, diagnosis and treatment of the disorder. Issues discussed include the primary and secondary symptoms of the disorder, developmental course, underlying causes, recognition in a clinical setting, diagnosis and treatment.