The object of research — destructive manifestations in professional activity and labor behavior, as well as the processes of deprofessionalization of individual and group subjects of labor. The definitions of “professional deformations” and “professional destructions” are analyzed. The difference in the essence of these concepts, reflecting the effect of different psychological mechanisms, is shown. “Professional deformation” leads to distortions in the structure of work activity or personality traits. “Professional destruction” leads to destruction (or destructive construction) of the structure of activity (changing its focus on other goals and results) or personality (orientation to the opposite labor and life values). The destructive effect is connected with the meaning-forming function of the motive that replaces the normative goal of the performed professional activity with another goal — personally significant and useful for the given performer, but socially harmful. “Pseudo-professionalism” (“false” professionalism) of the individual and group subject of labor is analyzed. Deprofessionalization of the subject is associated with the loss of professional identity, the destruction or non-acceptance of professional values. The problems of adaptation of a true professional in the group of pseudo-professionals (professional marginals) are considered. Conclusion: A profession as a social institution can counteract destructive processes of deprofessionalization of subjects of labor (primarily group ones) through the implementation of expert functions of professional associations.