Objectives: to evaluate the effect of different conditioning treatments on surface roughness and topography of dental cementum. Study Design: Extracted human canines were used for the present study. The mesial surface from the cervical third of the roots were ground flat with wet 600-grit silicon carbide paper. They were polished (up to 1/4 µm diamond paste) and treated as follows: 1) No treatment, 2) 35% H3PO4 during 15 s, 3) Clearfil SE Bond primer (SEB), 4) One-Up Bond F (OUB). The adhesive systems were applied following manufacturer?s instructions. SEB primer and OUB were removed from surfaces by washing and ultrasonic agitation with ascending ethanol solutions. Digital images of treated surfaces (5x5 and 15x15 µm) were obtained by means of an atomic force microscope (AFM) analysis. The average surface roughness (Ra nanometers) of the scanned areas was assessed. Data were analyzed by ANOVA and SNK multiple comparisons tests (p<0.05). Results: phosphoric acid treatment produced the highest mean roughness value, at all scan sizes. At 5x5 µm AFM images, for self-etch adhesive systems no differences in roughness were detected. At 15x15 µm, when One-Up Bond F was employed the lowest value was obtained. Conclusions: When phosphoric acid treatment was applied, cementum surface roughness increased and a strong demineralization with exposed collagen fibers could be observed.