The Marfan syndrome, a generalized inherited disorder, is usually diagnosed in young patients and is associated with a poor prognosis. With use of our diagnostic-retrieval system, we identified 28 patients with the Marfan syndrome who were 32 years of age or older at the time of diagnosis. These patients had at least two of four major diagnostic criteria for the Marfan syndrome--a confirmed family history, a long-limbed habitus, dislocated lenses, and disease of the aortic root. In these relatively older patients, some clinical findings (the ocular disorder and the family history) corresponded to the expected findings in younger patients with the Marfan syndrome; however, the proportion of those with cardiovascular disease was greater. Echocardiography has improved the potential for detection of the cardiac lesions, the most frequent cause of death in these patients. Early diagnosis of the Marfan syndrome is important so that complications of the cardiac lesions can be prevented or delayed and so that genetic counseling can be done at an appropriate time.