We present a case of a 43-year old woman with a long QT syndrome (LQTS). Despite her family history of several sudden deaths in close relatives the patient was misdiagnosed, being treated many years for epilepsy. Finally, after another series of syncopal spells she was diagnosed with LQTS. Although QTc interval was normal on surface ECG, the presence of notched T-waves and QT prolongation up to 543 ms on Holter recording were helpful in establishing the correct diagnosis, which was later confirmed by genotyping revealing G601S mutation in the HERG gene. The patient refused an ICD and despite beta-blocker treatment died suddenly several months later.