The methylphenidate transdermal system (MTS) patch is approved by the US FDA for use in children aged 6-12 years with attention-deficit hyperactivity disorder (ADHD). This delivery system permits sustained absorption of the drug through the skin and into the bloodstream. Methylphenidate (MPH) is a CNS agent thought to act on dopamine and noradrenaline (norepinephrine) pathways and thereby blocks the reuptake of these neurotransmitters into the presynaptic neuron. In children with ADHD, MTS patches releasing MPH doses of 10-30 mg over a 9-hour period (12.5-37.5 cm2 patch size) is steadily absorbed, with mean peak plasma concentrations of d-MPH (20-46.5 ng/mL) reached in approximately 8 hours. In well controlled trials in children with ADHD, patients administered MTS patches releasing MPH 10-30 mg over approximately 9 hours showed significantly greater improvements in their ADHD symptoms than placebo recipients. MTS patches are generally well tolerated in paediatric patients with ADHD, with treatment-emergent events being similar in nature to those reported with oral MPH. The majority of adverse events were mild to moderate in intensity.