Aim: To find the relationship between “divine proportion,” which exists between intercanine and intermolar widths in nature, and intercanine and intermolar widths in posttreatment and 1-year retention periods. Material and Methods: The sample included 25 patients (15 Class I and 10 Class II pretreatment malocclusions) with posttreatment Class I occlusions showing perfect alignment, according to the irregularity index. Anterior arch length, posterior arch length, anterior tooth length, posterior tooth length, anterior discrepancy, total discrepancy, and irregularity index were measured at pretreatment, posttreatment, and 1-year retention periods. Intermolar divine proportions, according to the available intercanine measurements, were calculated for each time period and compared with each other. In addition, differences between each stage of treatment for intercanine width, irregularity, intermolar width, anterior arch length, posterior arch length, anterior tooth length, posterior tooth length, anterior discrepancy, and total discrepancy measurements were compared with paired t tests. Pearson correlation tests were used to determine the correlation between divine proportions and each measurement. Results: A positive correlation was found between divine proportion and intermolar width for all stages of treatment. Conclusion: Orthodontic treatment seems to increase the correlation between divine proportion and intermolar width, but does not have an effect on the correlation between divine proportion and anterior irregularity. World J Orthod 2003;4:317–320.