The mass-resolved resonance enhanced two-photon ionization spectra of jet-cooled benzyl chloride were measured. Some low-frequency vibronic bands around the S-1-S-0 origin band were assigned to transitions of the internal rotational mode of the chloromethyl group. The internal rotational motion was analyzed by using the one-dimensional free rotor approximation. The conformation in the S, state was found to be that in which the C-Cl bond lies in orthogonal to the benzene plane. For the species with m/e 126, the transition energy of the internal rotational bands corresponded well to the potential energy values of V-2 = 1900 cm(-1) and V-4 = 30 cm(-1) in the S-1 state and the reduced rotational constant B values 0.50 and 0.47 cm(-1) in the S-0 and S-1, states, respectively. The B values obtained for the chlorine isotopomer (mle 128) were slightly different. The S, potential barrier height was found to be about 3 times larger than that for the So state. Molecular orbital calculations suggest that the difference between energies of the HOMO and LUMO with respect to the rotation of the chloromethyl group correspond approximately to the potential energy curve obtained for the S-1 state.