Directional atherectomy is an alternative device for treatment of highly eccentric or proximal coronary lesions considered less suitable for balloon angioplasty. We report a patient with exuberant neointimal proliferation, extending into the left main coronary artery, following directional atherectomy of the proximal target site in the left circumflex artery. This observation indicates that patients with mild left main disease have an increased risk to develop this complication following directional atherectomy.