A 2-year-old male developed generalized tonic-clonic seizure activity, tremor of limbs, muscle weakness, ataxia, and hypertonia after he swallowed 16 50-mg tablets of lamotrigine. His vital signs were normal, as were electroencephalography and laboratory investigation tests. The urine toxicologic screen revealed no other drugs. Treatment included midazolam and gastric lavage followed by activated charcoal and fluid loads. Symptoms resolved within 24 hours, and the child was discharged without any further complications. Serial blood samples revealed plasma lamotrigine levels at the high adult therapeutic range (3.8 mg/L) but a slow elimination rate. This is the first report of seizure activity reported in a patient receiving an overdose of lamotrigine. However, no evident concentration-effect–side-effect relationship has been established in children. Interestingly in this child, lamotrigine overdose presented exclusively with treatment-emergent neurologic abnormalities, sparing all other systems.