Using density-functional theory we calculate density profiles of an associating fluid in slit like pores as functions of two variables: The distance from the pore wall and the distance along the pore axis. Attention is focused on evaluation of the profiles characterizing the coexistence between two confined phases. We also calculate changes in the grand canonical potential connected with the formation of an interface between two coexisting confined phases. Specific calculations have been carried out for the associating, chain forming Lennard-Jones fluid adsorbed in a slitlike pore.