Adhesion forces between alumina substrates and spherical alumina particles were measured using an Atomic Force Microscope (AFM) colloidal probe technique. It was shown experimentally how nanoscale roughness of alumina substrates affects AFM adhesion force measurements. The adhesion force decrease was approximately five-fold between 1.5 and 12.0 nm root mean square (rms) surface roughness. Determining the roughness, which describes the actual geometry of the investigated surfaces, as accurately as possible, is crucial for predicting interaction forces. It was proven, that using a realistic value of the nanoscale rms is one of the most important parameters for accurately predicting adhesion forces between substrates. (C) 2013 Elsevier B.V. All rights reserved.