Objectives. To evaluate the upper lateral incisors crown dimensions in patients with hypodontia and to establish a possible correlation between the hypodontia type and the reduced dimensions of these teeth. Materials and methods. For this study we examined 52 dental casts of patients with hypodontia (except third molars) who were referred to the Orthodontics and Dentofacial Ortopaedics Department of “Carol Davila” University of Medicine and Pharmacy in Bucharest, between 2014 and 2018, divided as follows: 24 casts of patients with one absent tooth, 18 – of patients with 2 congenitally missing teeth and 10 – of patients with 3 or more congenitally missing teeth. The age range for the hypodontia subjects was 8-23 years old, with a mean of 13.76 years. The maximum mesiodistal crown dimensions of the upper lateral incisors were measured on the dental casts with a digital calliper. Statistical evaluation was performed using the Microsoft Office Excel 2016. Results and discussion. The prevalence of the microdont maxillary lateral incisors was 51.9%. Most of the upper lateral incisors showing morpho-dimensional coronary changes were noticed among female patients (32.7%) compared to 19.2% for the male sex. In the unilateral hypodontia of the upper laterals, the homologous lateral was always found as microdont. As for the patients with 2 congenitally missing teeth, we observed bilaterally microdont upper laterals, both in cases of second mandibular premolars and mandibular central incisors hypodontia. 80% of dental casts of the subjects with 3 or more congenitally missing teeth had microdont upper lateral incisors. Conclusions. Patients with hypodontia present a dimensional instability of the upper lateral incisors; the most obvious reductions of the largest mesiodistal diameters were registered in cases with severe hypodontia.