Fractal analysis provides novel physical insights into diffusion-limited reactions occurring at interfaces. In this paper, we analyze the fractal dimension Df values for the kinetics of the binding of gamma-globulin molecules to immobilized protein A on various supports (Unarska, M., et al., J. Chromatgr. 519, 53 (1990)). Fractal analysis data seem to indicate that Sepharose beads (Df = 2.22) increase the "ruggedness" or inhomogeneity of surfaces compared to microporous membranes (Df = 1.29) for chromatography applications. Copyright 1998 Academic Press.