Idiopathic isolated ostial left main artery stenosis is a rare disease with uncertain etiology, clinical course and prognosis. We described a young woman with no cardiovascular risk factors, who developed the disease 3 years ago with a bare-metal stent implanted in the left main artery ostium. She presented again with severe angina of rapid onset. Coronary angiography revealed ostial left main artery in-stent restenosis. A drug-eluting stent was successfully deployed over the previous stent with good angiographic result. The etiology and management of this disorder were briefly discussed.