Monte Carlo simulations (MC) were used to study the adsorption of a negatively charged peptide (ASP-ASP-ILE-ILE-ASP-ASP-ILE-ILE) dissolved in water onto charged surfaces and in vacuum onto neutral surfaces. When the peptide was placed between two charged surfaces, it always adsorbed sideways onto the positively charged surface even when it was initially positioned at the negatively charged one. The structure of water around the peptide significantly changed upon adsorption. The peptide adsorbed on a neutral surface heads-on. The subsequent addition of water does not seem to affect the location and orientation of the peptide at the surface. Our results indicate that dehydration of the peptide upon adsorption always happens to the residues that are closest to the surface independently of the surface's charge.