Aplastic anemia may be inherited or acquired. The distinction between these lies not in the age of the patient, but in the clinical and laboratory diagnoses. Adult hematologists must consider adult presentations of the inherited disorders, in order to avoid incorrect management of their patients. Physicians for adult patients must also realize that children with inherited disorders now survive to transition into their care. The major inherited bone marrow failure syndromes associated with development of pancytopenia include Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, and amegakaryocytic thrombocytopenia. The ages at presentation are highly variable, but often include individuals of adult age who have previously undiagnosed Fanconi anemia or dyskeratosis congenita. Many of the genes responsible for these disorders have been identified (12 Fanconi anemia genes, 3 dyskeratosis congenita genes, and 1 each for Shwachman-Diamond syndrome and amegakaryocytic thrombocytopenia). A high index of suspicion and specific testing of children or adults with what appears to be acquired aplastic anemia may identify inherited disorders. Correct classification of patients with aplastic anemia of any age is mandatory for their appropriate management.