Like most other classes of chemical mutagens, the aromatic amines (ArNH2) are metabolically activated to change the genetic code in DNA[1]. Mutagenic and carcinogenic ArNH2 are present in our environment.They have been identified in food,in cigarette smoke and etc. It has been verified that the metabolism of aromatic and heteroaromatic amines results in nitrenium ions (ArNH+) that can modify the nature and function of nucleobases of DNA[2].In this work we examine the complexes including ArNH+against adenine-thymine (AT)set, as one of the DNA base pairs.