Attention-deficit/hyperactivity disorder (ADHD) is diagnosed less often in Hispanics than in Caucasian patients. Furthermore, Hispanic patients with ADHD are undertreated. The reasons for these disparities are unknown, although difficulties with access to care among this population may offer a partial explanation. In order to improve treatment outcomes in Hispanic patients with ADHD, healthcare providers must reflect on the diversity of the Hispanic population, which consists largely of persons of Mexican, Puerto Rican and Cuban descent. In spite of the fact that Hispanics share a similar language, religion and belief system, there are other significant cultural differences among these subgroups. In addition, English-language proficiency and socioeconomic variables, factors that are known to influence healthcare outcomes, may also differ markedly among Hispanic subgroups. Therefore, strategies to improve the treatment of ADHD in the Hispanic population must include overcoming language barriers by increasing the availability of Spanish-speaking professionals and medical translators and using culturally sensitive diagnostic instrumentation. Furthermore, improving knowledge of cultural practices of particular Hispanic subgroups may improve the therapeutic relationship between patients and clinicians, facilitate the diagnosis of ADHD and allow healthcare providers to make appropriate treatment recommendations.