An ab intio two-body analytical potential function was constructed to describe Mn(II)-water interactions. Classical Monte Carlo (MC) and molecular dynamics (MD) simulations have been performed to study the hydration structure of Mn(II). The study was extended to a combined QM/MM-MD level in order to investigate the influence of higher (n-body) terms. The structure of the hydrated ion is discussed in terms of radial distribution functions, coordination numbers, and angular distributions. The results of the QM/MM-MD simulations have been found to be much closer to the experimental values, proving that many-body effects play an important role in the description of the hydrated Mn(II) ion.