Motivated by recent developments concerning coloration and energy storage in lithium intercalated nanostructural TiO2, quantum chem. Hartree-Fock calcns. have been carried out to study lithium atom intercalation in rutile and anatase. Equil. geometries and effective at. charge were obtained for the rutile (110) and anatase (101) clean surfaces. Li-induced local one-electron energy levels were found in the gap between the upper valence band and the conduction band and could be attributed to Ti3+ states. The absorption energies obtained are compared with available exptl. data. The equil. positions of the Li atom and its surrounding host atoms have been calcd. for both structures. The results predict a higher possibility of lithium intercalation in the anatase structure than in rutile.