In this paper, a means of determining the viscoelastic properties of adsorbed polymer layers under compression is presented. The technique allows rheological properties to be measured on a nanoscopic scale, and revolves around the use of a Surface Force Apparatus (SFA) that has been specially modified for such a purpose. The experiments were carried out by applying an oscillatory motion to one mica surface and monitoring the response of the second confining surface to this motion. The coupling of the motion between the two surfaces is characteristic of the material in the gap and allows the viscoelastic properties of the material to be determined as a function of its confinement. In developing such a technique, the aim was to bridge the gap between the nanoscopic (equilibrium) view obtained from surface force measurements and the macroscopic (dynamic) view obtained from traditional rheological measurements. Results obtained on a PEO/PS system in toluene and a PMMA/PHSA system in a decahydranaphthalene solvent are presented here. The results indicate a significant change in the behavior of the system from being predominantly viscous away from polymer overlap to being predominantly elastic where there is overlap.