• Objective: To review the diagnosis and treatment of attention-deficit/hyperactivity disorder (ADHD) in adults. • Methods: Qualitative assessment of the literature. • Results: ADHD in adults is characterized by symptoms such as difficulty getting started on tasks, variable attention to details, difficulties with self-organization and prioritization, and poor persistence in tasks that require sustained mental effort. These symptoms result in impaired performance in academic, occupational, and social spheres. To meet diagnostic criteria for ADHD as an adult, the disorder must have been present in childhood (possibly undiagnosed). Adult ADHD can co-occur with other psychiatric disorders, making the differential diagnosis challenging at times. Treatment modalities include patient education, pharmacologic therapy, and psychosocial interventions. • Conclusion: It is important for primary care physicians to identify patients with adult ADHD and ensure that they receive effective treatment.