We employed the Raman spectroscopy and the MP2 and DFT ( with the MPWB1K, M05, M05-2X and MPW1B95 functionals) calculations to study the interaction of cytosine with SWCNTs (single-wall carbon nanotubes). The Raman spectra of SWCNT and SWCNT-cytosine films showed that the non-covalent interaction results in a down-shift of the frequency of the most intensive band of the SWCNT at 1590 cm (1) ( the G-mode). The interaction energy in the complex formed by cytosine with a fragment of the zigzag(10, 0) SWCNT calculated at the MP2/6-311++G(2d, p) level of theory is -62.4 kJ/mol. (c) 2008 Elsevier B.V. All rights reserved.