Pharmacotherapy is frequently used to treat symptoms of attention-deficit/hyperactivity disorder (ADHD), the most common neurobehavioral disorder of childhood. There are a few reported cases of overdose for suicide attempts or abuse with methylphenidate in current literature. Majority of these cases fully recovered after supportive therapy. We present a patient who ingested 3240 mg long acting methylphenidate for suicide attempt. He experienced increase in heart beat rate and blood pressure but he did not have additional symptoms. Although no serious neurological or cardiovascular event happened in this case, the supervised stimulant use is needed in child and adolescent population. Further studies are needed to evaluate the effect of methylphenidate overdose.