Configurations of C-60 fullerene derivatives (C60COOCH2, C60COOHCH3) are optimized using B3LYP method at 6-31G* level. The calculated charge distributions by Natural Population Analysis show that the charge transfers exist between the functionalized group and parent C-60. Then, the excited state properties of title species are calculated by the time-dependent density functional theory. It is shown that the fullerene derivatives make a small red shift of the absorption spectra in comparison with the C-60 cage itself and the calculated electronic absorption spectra are in good agreements with their observed values. (C) 2003 Elsevier B.V. All rights reserved.