Esthetics is one of the important treatment goals in prosthetic dentistry. The correct choice of anterior teeth in terms of size and appearance is very effective to the success of the prosthetic treatment. One of the ways to determine the size of the anterior teeth is using facial indices. The aim of this study was to determine the relationship between the upper intercanine width and the inner intercanthal distance. In this cross-sectional study, 114 patients admitted to the Guilan Faculty of Dentistry (62 women and 52 men), over the age of 18 who were eligible, were randomly selected. Inner intercanthal distance and the distance between the tips of the upper canines were measured with a digital caliper. Data were analyzed using Pearson's correlation coeffi cient analysis, independent and paired t-test. The mean of intercanthal distance and intercanine width was 30.75 and 34.56mm, respectively. A signifi cant relationship existed between intercanthal distance and intercanine width. It was found the biometric ratio of 1 to 1.13 could be used to estimate intercanine width. These results could be used as a helpful guide for selection of anterior teeth width in the population of patients. This biometric ratio may not be reliable in women.