The study aims at assessing the relationship between adaptive functioning and severity of symptoms among children with Attention Deficit Hyperactivity Disorder (ADHD). A descriptive correlation design was used. The sample consisted of (100) children diagnosed by a psychiatrist as being affected with ADHD at psychiatric outpatient clinic in Mansoura University Hospitals (MUH).Â The collection of data was carried out through assessing the socio economic state of child parents using Socio Economic Status scale for health research in Egypt, ADHD level using Conners Parent Rating Scale (CPRS) and the adaptive functioning using Vineland Adaptive Behavior scale (VABS). Results revealed highly significant negative correlation between ADHD severity and adaptive behavior (communication, socialization, DLS, and motor skills) at p<0.001. There is significant negative correlation between adaptive functioning and ADHD sub domains; conduct, psychosomatic, impulsive hyperactive and hyperactivity index at p<0.001, anxiety at p=0.036, while not significant with learning problem at p=0.219. In conclusion, there is high significant relationship between adaptive functioning and severity of ADHD.Â Therefore, it is recommended for nurses to enhance adequate training about adaptive behavior for those children to minimize their dependence and disability.