Introduction. The problem of professional deformation of teachers remains highly relevant due to the special social significance of pedagogical activity and the increasing risk of developing destructive personality changes under the influence of long-term performance of professional duties. Psychological science has accumulated considerable material on this issue, but researchers have not yet sufficiently studied the dynamics of deformation changes depending on teaching experience, which complicates the development of differentiated preventive programs. Theaim of the work is to identify the features of professional deformation of teachers with different lengths of teaching experience. Materials and methods. The study involved 84 teachers of secondary schools in the city of Bor, Nizhny Novgorod Region. The authors divided the subjects into three groups: the first - teachers with experience up to 5 years, the second - with experience from 5.5 to 10 years, and the third - with experience from 10.5 years and more. We used the questionnaire “Assessment of professional and pedagogical deformations” by E.F. Zeer and A.I. Pavlova. The authors carried out statistical analysis of significant differences using the nonparametric Mann-Whitney U-test. Research results and discussion. The results show that the most pronounced deformation in the overall sample is role expansionism, and the least pronounced is conservatism. The majority of the studied professional and pedagogical deformations are at low and medium levels of severity. The study found statistically significant differences between groups with different experience on such parameters as pedagogical aggression, didacticism, dominance, role expansionism, social hypocrisy, and behavioral transfer. At the same time, at the initial stage of professionalization, the structure of deformation manifestations remains relatively homogeneous. The most significant differences emerged when novice and experienced teachers were compared.  Conclusion. Professional deformation of teachers is a dynamic and selective process. The first years of work are characterised by a relatively stable manifestation of the process, while qualitative changes increase with experience and mainly affect the role and communication aspects of behaviour. These findings provide a basis for developing targeted programmes to prevent professional deformation.