A quantitative evaluation, by atomic force microscopy measurements, of the nano-topography of single and double stranded DNA functionalized Au surfaces is carried out. The two-dimensional fractal dimension was quantified for the Au surface in 0.9 ± 0.1 and 2.1 ± 0.3 from 1 μm × 1 μm and 5 μm × 5 μm scans, respectively. It was quantified in 2.1 ± 0.1 and in 2.4 ± 0.3 for the Au surface after immobilization of single-stranded DNA film and in 2.0 ± 0.1 and 1.9 ± 0.3 for the Au surface after hybridization, from 1 μm × 1 μm and 5 μm × 5 μm scans, respectively. These results indicate a topographical conforming effect of the DNA films toward a two-dimensional Gaussian surface.