Introduction: Dento-maxillary disharmony (DMD), now referred to as Dental Arch Disharmony (DAD), is a highly prevalent anomaly encountered by orthodontists in their daily practice. Objective: The aim of our study is to estimate the prevalence of dento-maxillary disharmony at the dento-facial orthopedics (DFO) department of the Blida University Hospital Center in Algeria, in order to position this disharmony relative to other orthodontic anomalies, estimate its evolution, and compare the results obtained with other studies conducted in different countries. Materials and Methods: This descriptive epidemiological study was conducted at the DFO department of the Ahmed Zabana Dental Clinic at the Blida University Hospital Center, focusing on 80 cases of dento-maxillary disharmony out of 188 cases in the orthodontic population. The study spanned a period of one month and five days, from May to June 2022. Results: Analysis of our records reveals that 42.55% of the orthodontic population exhibits dento-maxillary disharmony, with a predominance of females at a rate of 64%. The most frequent age group is children aged between 6 and 12 years (49%). During our study, the prevalence of relative macrodontia dento-maxillary disharmony was the most dominant, accounting for 86%, followed by 8% for dento-maxillary disharmony due to microdontia, and 6% for mixed cases. Conclusion: The high frequency of dental arch disharmony, as demonstrated in our study and similar studies, emphasizes the need to understand the factors contributing to its development in order to establish prevention and interception strategies, thereby enabling early management of this anomaly.