Aim: To evaluate the Bolton ratios in Brazilians with natural, normal occlusions. Methods: Thirty-five dental casts of Brazilian Caucasians with a natural, normal occlusion from the files of the Postgraduate Program in Orthodontics of the Methodist University of São Paulo were scanned in three dimensions. On the scanned images, the greatest mesiodistal distance of each tooth from right first molar to left first molar was measured with Geomagic Studio 5 software. The Bolton ratios were then calculated. Results: The anterior ratio amounted to 78.66% (SD ± 2.72) and the total ratio to 91.58% (SD ± 2.20). Conclusion: The anterior, but not the overall, ratio was significantly different from the ratio suggested by Bolton. World J Orthod 2010;11:67–70.