Neurofibromatosis type 1, also called von Recklinghausen's disease, is a hereditary congenital disorder that affects tissues of neuroectodermal or mesodermal origin. This disease has various manifestations, including pigmented skin lesions, cutaneous neurofibromas, skeletal abnormalities, and tumors of the central/peripheral nervous and gastrointestinal systems, and vascular abnormalities. Because of vasculopathy, part of the vessel wall may be replaced by neurofibromatosis tissue. Involvement of the internal thoracic artery is, however, extremely rare. Off-pump coronary artery bypass grafting using the left internal thoracic artery was performed for coronary arterial disease in a patient with neurofibromatosis, and the residual left internal thoracic artery vessel pathology was investigated. The left internal thoracic artery vessel showed intimal proliferation, medial thinning, and fragmentation of elastic tissue. However, these findings were not typical for von Recklinghausen's neurofibromatosis. Internal thoracic artery graft selection was feasible for coronary artery bypass grafting in a patient with neurofibromatosis type 1.