Inattention, hyperactivity and impulsivity constitute the core diagnostic criteria for attention deficit hyperactivity disorder (ADHD) children. Patients generally suffer from sleep disturbance and malnutrition that can account for tiredness during the day, poor concentration, poor eating and depressed mood, along with anemia and an n-3 polyunsaturated acid deficiency. The change of ADHD behavior in children (9–12) was studied, following 10 weeks of treatment with a polyunsaturated acid mixture on six variables: cooperation, mood, concentration, homework preparation, fatigue and sleep quality. Iron status was also examined. Polyunsaturated acid administration was associated with significant improvement in quality of life, ability to concentrate, sleep quality and hemoglobin levels.