RESUMEN
Autoimmune diseases occur as a consequence of activity of one's own immune system against the body's own cells. Depending on target cells, autoimmune diseases are divided into organ-specific, i.e. those that affect only one organ or organ system, and systemic autoimmune diseases. In a large number of diseases belonging to this group, oral mucosa may be affected and the clinical picture can be very diverse. Oral lesions may occur in the earliest stages of autoimmune diseases, and some of them may be the first, or even the only manifestation. Given that many of these diseases can have serious life prediction, it is important to recognize changes in oral mucosa, diagnose them and start appropriate treatment on time. This paper deals with autoimmune diseases that often manifest on oral mucosa, such as autoimmune blistering diseases and lupus erythematosus.