This contribution deals with the evaluation of blasted surfaces used for forming adhesively-bonded joints. It was observed that surface quality evaluation by R-a arithmetic mean average roughness-parameter, only was insufficient. Experimental results show there is no direct correlation between surface roughness and bonded joint strength, because surface roughness and surface irregularity are not identical terms. Fractal analysis is presented as a suitable tool for surface irregularity evaluation. Fractal dimension is shown as an additional parameter for bonded joint strength prediction. (c) Koninklijke Brill NV, Leiden, 2008