Hydrogen recycle and inventory in first-wall materials of fusion reactors are strongly affected by surface and bulk properties—such as coefficients for hydrogen adsorption on the surface, and diffusion in the bulk. Here we present results for the sticking coefficients of molecular and atomic hydrogen on palladium, obtained from measurements of retained hydrogen subsequent to exposure to H2 and sub-eV H0 fluxes. Characteristic curves of the retained hydrogen versus incident fluence were used to determine the sticking coefficients αm and αa for H2 molecules and H0 atoms, respectively.