The CH2Cl2 + OH- reaction in aqueous solution was investigated using combined quantum mechanical and molecular mechanics approach. We present analysis of the reactant, transition, and product state structures and calculate the free energy reaction profile through the CCSD(T) level of the theory for the reactive region. Our results show that the aqueous environment has a significant impact on the reaction process, raising the reaction barrier by similar to 17 kcal/mol and the reaction energy by similar to 20 kcal/mol. While solvation effects play a predominant role, we also find sizable contributions from solvent-induced polarization effects.