We use molecular dynamics to study the kinetics of surface enrichment (SE) in a stable homogeneous mixture (AB), placed in contact with a surface which preferentially attracts A. The SE profiles show a characteristic double-exponential behavior with two length scales: -, which rapidly saturates to its equilibrium value, and +, which diverges as a power-law with time (+ ∼ tθ). We find that hydrodynamic effects result in a crossover of the growth exponent from θ≃0.5 to θ≃1.0. There is also a corresponding crossover in the growth dynamics of the SE layer thickness. © 2010 American Institute of Physics.