Adsorption of associating hard spheres and particles interacting via the Lennard-Jones potential at a Lennard-Jones adsorbing wall is studied using the density functional theory. A model of association with one site per particle is considered. To test the theory we have also performed Monte Carlo simulation in the canonical ensemble for a Lennard-Jones associating fluid at high temperatures and fur hard associating spheres. Next, the influence of association on the wetting behavior of the fluid-solid interface is investigated. It is shown that the prewetting transition in associating systems is considerably influenced by the association processes.