Aplastic anemia is mostly an acquired disorder, in minor cases, they are inherited forms of which Fanconi anemia is the most common. Cytogenetic analyses were conducted on P.B lymphocytes of 13 patients with Fanconi anemia and 9 cases with acquired A.A already diagnosed on clinical basis. MMC was used as an oxidative stress to induce chromosomal damage and vitamin E was used as an antioxidant. Comparison of induced chromosomal breakage frequency to base line culture , distinguished the 2 diseased groups .Vitamin E provided partial correction of the damage. The test is important to rule out FA since management options are different. Anti oxidants can be used as an adjuvant therapy.