We report the case of a 26-year-old man who died suddenly 9 days after an episode of flu. Microscopic examination of the left anterior descending coronary artery showed an eccentric fibroatheromatic plaque complicated by thrombosis, endothelial erosion and extensive T-cell and macrophage infiltration. Frozen sections of the thrombotic coronary segment, analysed for different infective agents by polymerase chain reaction (PCR) and reverse transcriptase (RT)-PCR, showed positive amplification for an enteroviral genome. Enteroviral infection may play an important role in coronary plaque instability and may precipitate thrombotic occlusion.