Objectives: To increase the awareness of clinicians and cardiologists as to the sequelae of missed Kawasaki disease (KD) presenting in young adults; one in four patients with untreated KD will develop coronary aneurysms. Background: Coronary artery aneurysms that result from the acute arteritis of Kawasaki disease (KD) in childhood may remain silent for decades. Patients with aneurysms due to missed KD in childhood may present in adulthood with signs of acute ischemia. Methods: To investigate the possibility of missed KD in young adults in Egypt, we reviewed angiograms of patient’s ≤ 40 years of age presenting with symptoms of myocardial ischemia at a government hospital, a private cardiac catheterization laboratory, and a private imaging facility. Data collected included demographic characteristics, medical history, traditional cardiovascular risk factors, electrocardiographic, and angiographic findings. Results: A total of 580 angiograms (conventional and multi-slice computed tomography) were reviewed. Coronary artery aneurysms were noted in 46 patients (7.9 %) of whom nine presented with myocardial infarction and 37 had unstable or exertional angina. After review of the angiograms by two experienced cardiologists, the likelihood of antecedent KD as the cause of the aneurysms was classified as definite (n=10), probable (n= 29), or equivocal (n=7). Compared to the definite and probable groups, the equivocal group had more traditional cardiovascular risk factors, smaller sized aneurysms, and fewer coronary arteries affected. Conclusions: In a major metropolitan center in Egypt, 6.7% of adults age 40 years or younger undergoing angiography for evaluation of possible myocardial ischemia had lesions consistent with antecedent KD. Because of the unique therapeutic challenges associated with these lesions, adult cardiologists should be aware that coronary artery aneurysms in young adults may be due to missed KD in childhood.