The 4`-aminomethyl-4.5`,8-trimethylpsoralen (AMT) has been used as intercalating DNA binding drugs in the photo-chemotherapy of skin diseases. The conformation and stability of DNA octamer duplex, d (GGGTACCC)₂, cross-linked with AMT has been studied by NMR spectroscopy. All the proton resonances of the psoralen cross-linked octamer were assigned and meting temperature studies were carried out based on the assignment of the proton resonances. The aromatic proton chemical shift data suggest that the conformation of the helix cross-linked with psoralen is destabilized more to furanside of the psoralen. possibly due to the protrusion of the aminomethyl side chain of the psoralen.