Anticonvulsant hypersensitivity syndrome (AHS) is a rare but life-threatening adverse effect of aromatic anticonvulsants such as phenytoin, phenobarbital and carbamazepine, although there is extensive experience with AHS related to these anticonvulsants. Very few cases of lamotrigine-associated AHS have been reported in bipolar patients and most reported cases were published in non-psychiatric journals. The authors describe here the occurrence of an AHS in a 48-year-old bipolar woman who was treated with lamotrigine, valproic acid and venlafaxine for her depressive symptoms. She developed a high fever, generalized maculopapular rash, pancytopenia, pneumonitis and hepatitis after we added lamotrigine to valproate and venlafaxine. These adverse drug reactions resolved after the discontinuation of lamotrigine and valproate, and the administration of oral antihistamine and corticosteroid. Our case demonstrates that the most important steps in the management of lamotrigine-associated AHS are to recognize the disorder, discontinue the offending anticonvulsants, provide supportive care in an inpatient setting, and treat with antihistamine and steroids when appropriate.