The smoking cessation agent varenicline acts as a partial agonist on alpha(4)beta(2) nicotinic acetylcholine receptors. Although debated, several reports have linked varenicline therapy to an increased risk of suicidal thoughts and/or suicide. In addition, several non-fatal overdose cases have been reported. In this report, we utilised a sample preparation procedure suitable for postmortem samples and gas chromatography coupled to mass spectrometry to analyse samples obtained from a suicidal case in which ingestion of an overdose of varenicline had occurred. Extremely high concentrations of varenicline (> 250 ng/ml) were detected in the blood of the deceased, in addition to high concentrations in urine and vitreous humour. To the best of our knowledge, similar high concentrations have not been reported yet. Although, with respect to the mechanism of death in this case, confounding factors were concomitant ethanol consumption and, importantly, potentially fatal hypothermia, this is the first report of a fatality associated with the ingestion of an overdose of varenicline.