We present results of classical trajectory calculations on the sticking of hydrogen atoms to the basal plane (0001) face of crystalline ice, I-h. The sticking probability is found to decrease with both incidence energy (E) and surface temperature (T,). At the surface temperatures studied, the sticking probability can be fitted to a simple decay function: P-s = 1.5 e-(E(K)/175) at T-s = 10 K, and P-s = 0.85 e(-E(K)/175) at T-s = 70 K. In the trapped state, the adsorbed hydrogen atom is located on top of the ice surface, over the center of a surface hexagonal ring, interacting with all water molecules forming the ring. The calculated physisorption energy of the adsorbed atom is approximately 400 50 K. The results of our calculations are compared with the experimental and theoretical data for amorphous ice surfaces. At T, = 10 K, our values for the sticking probability are higher than those of Buch and Zhang [Buch, V.; Zhang, Q. Astrophys. J. 1991, 379, 647], which is attributed to differences in surface topology. Our sticking probability values are lower than those of Masuda et al. [Masuda, K.; Takahashi, J.; Mukai, T. Astron. Astrophys. 1998. 330, 243]. which we attribute to an incorrect implementation of the H-H2O potential in their work. The experimental results available on hydrogen formation on amorphous ice are in good agreement with our results, if the assumption is made that all H-atoms that stick will recombine. Our calculations then suggest that the formation of H-2 through recombination of H-atoms adsorbed on the surface is efficient enough to compete with the cosmic destruction of H-2.