Introduction: DSM-IV criteria are generally used to diagnose Attention Deficit and Hyperactivity Disorder (ADHD); however, this is complex and can be expensive. Consequently, several specific scales or behavioral (psycho-neurological tests) tests have been introduced, which leads to the need of knowing about their usefulness in ADHD. Purpose: To identify, synthesize and evaluate the best available evidence on the usefulness of the Conners and intelligence tests in the diagnosis of ADHD in the population between 6 and 19 years. Methods: This is a systematic review of studies of diagnostic tests that evaluated the diagnostic validity, reliability and effectiveness of Conners and intelligence tests in the diagnosis of ADHD in population between 6 and 19 years, using the PubMed database, LILACS, Cochrane, DARE and National Guideline Clearinghouse, published until February 2012, in English and Spanish. The articles that met the inclusion criteria were assessed for methodological quality by two independent researchers who reached a consensus. Results: Of the 110 studies found initially that address this issue, ten studies were included: three medium quality systematic reviews, seven good quality diagnostic test primary studies, and five evidence-based clinical guidelines. Conclusions: The validity, reliability and effectiveness of Conners test and the intelligence test are heterogeneous, and clinical practice guidelines do not recommend their use. The use of these methods is recommended only in the overall assessment of the individual with the disorder.