As a test for comparing explicit and implicit treatments of solvation, conformational analyses of the octapeptide angiotensin II have been carried out using molecular dynamics and Monte Carlo simulations. The molecular dynamics treatment uses an explicit atomic description of the solvent whereas a solvent-accessible surface-area calculation is introduced in the Monte Carlo procedure in order to mimic the effect of the solvent surrounding the solute molecule. Several hydration models proposed in the literature have been considered, and the results obtained by the Monte Carlo procedure indicate that most of these models lead to different behaviors of the peptide in water. The results obtained with each set of solvation parameters are compared with those obtained from molecular dynamics. This work demonstrates that the choice of the solvation parameters is crucial for a proper simulation of the effect of the hydration free energy on the conformations of peptides. When the appropriate parameters are used to simulate solvent effects, good agreement is obtained between molecular dynamics and Monte Carlo approaches. Considering the CPU cost of molecular dynamics simulations with explicit solvent molecules, Monte Carlo calculations using empirical solvation models appear to be more appropriate to sample conformational space of solvated chain molecules.