Abstract: Objective To investigate the clinical features of comorbidity of attention deficit/hyperactivity disorder (ADHD) with allergic rhino-conjunctivitis in children. Methods Medical records of 4 patients who were diagnosed as allergic disease with ADHD and treated in Beijing Shijitan Hospital affiliated to Capital Medical University from May 2015 to September 2017 were retrospectively investigated and its related literatures were reviewed. Results Four children (2 boys and 2 girls) aged 10-14 years went to other hospitals for presentations of extremities hyperactivity, attention-deficit, poor academic performance, etc, and they were diagnosed as ADHD. They went to Beijing Shijitan Hospital for the concurrent nasal obstructive, sneeze, nasal drips and frequent blinking and cough. Allergen tests showed that they were severely allergic to dust mites, pollen, fungi and a variety of food.The diagnosis of allergic rhino-conjunctivitis with ADHD was established. The treatments for these four children were scheduled including:avoiding eating certain foods and keeping a diary for diet, giving specific immunotherapy for major allergens. Regular follow-up revealed that the ADHD symptoms had relieved after the management of allergic rhino-conjunctivitis, and ADHD didn't recurred after stopping the drug treatments. Conclusion It is necessary to inquiry the history of allergic disease in children with ADHD (e.g., allergic rhino-conjunctivitis or asthma) and conduct allergen tests for inhalation and foods. The subsequent specific immunotherapy will be beneficial to relieve ADHD.