Ab initio (RHF, MP2, CASSCF and CASPT2) calculations in the ground and the lowest excited singlet states have been performed for indole-water clusters. The calculations reveal a remarkable role of the lowest 1 πσ * state in the photochemistry of these systems: indole in the 1 πσ * state ejects an electron into the aqueous environment, leading to the formation of a charge-separated state. The computational results indicate that indole-water clusters are good models for the investigation of the mechanistic details of the electron solvation process occurring upon UV photoexcitation of indole and tryptophan in liquid water.