Both the effective fragment potential method and fully ab initio HF and MP2 methods have been used to study solvation effects on the conformational potential energy surfaces of ACh and ATCh. Comparisons of hydrated geometries and relative energies show that EFP1 can generate results quite close to the much more time-consuming ab initio calculations. Hydrated structures of ACh and ATCh prefer bridged water structures. Very limited effects from the solvation have been observed in ACh and ATCh. In both the gas and aqueous solution, ACh prefers the gauche NCCO arrangement, whereas ATCh favors trans NCCS. Possible interpretations are discussed.