Chloroethylnitrosoureas　(CENUs)　are　important　clinical　antitumor　agents.　In　the　present　work,　the　quantitative　structure-activity　relationship　(QSAR)　of　CENUs　is　investigated　by　ab　initio　computations　at　MP2/6-311G(d,p)　level　of　theory.　The　activation　energies　of　the　electrophilic　center　formation　on　the　α-　and　the　β-earbon　(Eaα　and　E　aβ),　as　well　as　the　octanolwater　partition　coefficient　(LogP),　are　selected　as　structural　parameters.　37　kinds　of　CENUs　with　experimental　anticancer　therapeutic　index　(TI)　are　selected　as　models.　Through　numerical　fitting　for　the　computational　data　with　the　experimental　anticancer　TI,　a　computational　formula　is　established　to　predict　the　anticancer　activity　of　CENUs.　The　correct　discrimination　ratio　by　computations　according　to　the　experimental　anticancer　TI　comes　up　to　94.6%　through　a　five　degrees　classification.　©　2007　IEEE.